Just as with any other operating system, to use a Windows computer or device, you need a user account. This is one of those concepts that a lot of us take for granted and we believe we know what it is and what it does. But do you know everything there is to know? This guide will share the detailed definition of the user account, the username, and their attributes. You will also learn how to list all the user accounts that exist on any system with Windows and how to see which users are signed in at the same time.\r\n\r\n\r\nWhat is a user account in Windows?\r\nA user account is a collection of settings that is used by Windows and other operating systems for understanding your preferences and for controlling the files and folders you access, the tasks you are allowed to perform, the devices and resources you are allowed to use, and so on. User accounts are the only way of authenticating and receiving the authorization to use your Windows device. Without logging in with a user account, you cannot use Windows. User accounts are also used to separate the people who use the same computer or device and make sure that they do not mess with each other\\'s files, settings or applications. When multiple people use the same computer, user accounts keep everyone\\'s files, settings, and applications private.\r\n\r\nFor example, on a Windows computer that is used by the whole family, you can have a user account for each parent, a user account for each child and a user account for guests that come to visit and may need to use the computer temporarily.\r\nWhat is the connection between a Microsoft account and a user account?\r\nIn Windows 7 or older versions of Windows, we only had local user accounts. These user accounts had a name which was unique only to the computer or the business network where they existed. However, in Windows 8.1 and Windows 10, we also have Microsoft accounts. These accounts have an e-mail address that is registered with Microsoft, and they can be used across Microsoft devices and services. For example, with the same user account that is also a Microsoft account, you can sign into your Windows laptop, your Xbox One console, a smartphone with Windows 10 Mobile, and so on. This isn\\'t possible with local user accounts.\r\n\r\nIf you want to learn more about Microsoft accounts and whether they are worth using, read this article: Should you use a local or a Microsoft account in Windows 10?\r\nWhat are the attributes of a user account in Windows?\r\nAny user account has the following characteristics:\r\n\r\n \tthe username or account name\r\n \ta unique identifier\r\n \tthe password\r\n \ta user account picture\r\n \tthe user type\r\n \tthe user group\r\n\r\n\r\n\r\n\r\nUser account, Windows\r\n\r\nNext, we will take a look at all the major properties, in detail.\r\nWhat is the username in Windows?\r\nThe username is the display name that you give to a user account. Microsoft also calls it the account name. You can set the username to anything you wish, and it doesn\\'t have to be unique on your device.\r\n\r\n\r\n\r\nUser account, Windows\r\n\r\nWhen entering the username or the account name, you can use lowercase and uppercase letters, spaces and numbers. You can\\'t use special characters (!,+ and so on) like the ones shown in the screenshot below. They are not allowed for user names in Windows.\r\n\r\n\r\n\r\nUser account, Windows\r\n\r\nAlso, usernames in Windows cannot have more than twenty characters, including spaces.\r\nWhat is the SID of a user account in Windows?\r\nFor each user account, Windows also generates a unique Security Identifier (SID) that\\'s not displayed in the user interface but is used internally for storing your settings. The SID has a unique value of variable length, and it looks like this: S-1-5-21-1180699209-877415012-3182924384-500.\r\n\r\n\r\n\r\nUser account, Windows\r\n\r\nWhile display names may not be unique, the hidden SID is always unique. Each time a user account logs on, Windows retrieves the SID for that user from its database of user accounts. Then, it uses the SID to identify the user in all subsequent interactions. If you would like to read more about this concept, Microsoft offers some technical documentation here: Security Identifiers.\r\n\r\n\r\nWhat is the password for a user account?\r\nIf you are using computers, e-mail services, and smartphones, the concept of passwords shouldn\\'t be foreign to you. A password is the most basic way of securing an account and making sure that only its owner can access it. On a computer with Windows, each user should have their unique password that is not known by other users.\r\n\r\n\r\n\r\nUser account, Windows\r\n\r\nEvery user account has a password. However, this password may be blank, if you are using local user accounts. Windows 8.1 and Windows 10 have also introduced the concepts of PIN and Picture Password which do not replace the traditional password but only complement it. You can create a PIN or Picture Password and use them to log in faster. They cannot be set up without first providing a standard alphanumeric password. To learn more about these concepts, read this guide:\r\n\r\n \tHow To Create & Login With A PIN Or A Picture Password In Windows 10\r\n \tIntroducing Windows 8 & 8.1: How to Switch Between Sign-In Options\r\n\r\nWhat is the user type in Windows?\r\nEvery user account has a type assigned to it. In Windows 7 and earlier versions, we used to have only three types of user accounts:\r\n\r\n \tAdministrator \u2013 user accounts that have complete control over the operating system, its apps, and settings.\r\n \tStandard \u2013 this is a limited type of user account which can only use existing software and cannot install applications of any kind. Also, these user accounts cannot modify system settings that affect other users.\r\n \tGuest \u2013 a limited type of user account. There is only one Guest user account on a Windows 7 or Windows 8.1 device, and it has no password. It is meant only for temporary access to the PC, and it can be used only for running existing applications. This user account type cannot modify any system settings. This kind of account no longer exists in Windows 10. To learn more about this subject, read this guide: You can\\'t enable the Guest account in Windows 10. Stop trying!\r\n\r\nIf you would like to learn how to change the user account type, in Windows, read this tutorial: 3 ways to change the type of a user account (Standard or Administrator), in Windows.\r\n\r\nWindows 8 and Windows 10 have introduced two new kinds of accounts: the Microsoft account and the local account. Both of them can be set as administrator and standard user accounts. To learn more about these accounts and when to use one or the other, read the following:\r\n\r\n \tShould you use a local or a Microsoft account in Windows 10?\r\n \tIntroducing Windows 8.1: Should You Use a Local or a Microsoft Account?\r\n\r\nWhat is a user group in Windows?\r\nA user group is a collection of multiple user accounts that share common security rights in Windows. A user account is a member of at least one user group while user groups can have any number of members, including none. A user account that is part of a group inherits all its permissions as well as its restrictions.\r\n\r\nIf you want to learn in detail what user groups are, why Windows uses them and how, you should read this guide: What Is A User Group In Windows & What Does It Do?\r\nWho can create accounts in Windows?\r\nMany parties can create user accounts:\r\n\r\n \tWindows creates several user accounts when you install it or when you use certain features. For example, Windows 7 creates the following user accounts: Administrator, Guest and HomeGroupUser$. The first two user accounts are disabled and must be manually enabled by a user account with administrator permissions. The HomeGroupUser$ is enabled and used to provide homegroup access to your PC or device.\r\n \tAdministrators can create any number of user accounts.\r\n \tThird-party software and services can create hidden user accounts that are used to run different services. The most common example is virtualization software like VMware Player: it creates a user account named ___VMware_Conv_SA___ which is used to run VMware Converter standalone server jobs.\r\n\r\nWhere do you find all the user accounts that exist in Windows?\r\nThere are many methods for displaying the user accounts that exist on your Windows device. If you have a Professional, Ultimate or Enterprise edition of Windows 7 or the Pro or Enterprise edition of Windows 8 or Windows 10, you can use the Computer Management tool. Complete step by step instructions are shared in this guide: The Geek\\'s Way of Managing User Accounts and Groups in Windows.\r\n\r\nIf you have another edition of Windows, you can also use the Command Prompt to find this information. Complete step by step instructions are shared in this guide: How to Generate a List with All the User Accounts Found in Windows.\r\nHow do you know which user accounts are signed in?\r\nThe Task Manager is a useful tool for seeing which user accounts are signed in to your Windows PC or device and what apps they are running. Press CTRL+Shift+Esc to start the Task Manager. If it is displayed in its compact view, press \\"More details\\" and then go to the Users tab. Now you can see a list of the user accounts that are signed into your Windows device and their status.\r\n\r\n\r\n\r\nUser account, Windows\r\n\r\nIf you would like to learn how to use the Task Manager so that you keep track of who is signed in, read this guide: How to Manage Signed In User Accounts with the Task Manager.\r\nConclusion\r\nNow you know everything there is to know about user accounts, usernames and so on. If there are any questions that we have not answered, let us know using the comments below. We will do our best to help and improve this guide.