A UAC prompt is shown, asking for permission when an application wants to make a system change like changes that affect other user accounts, modifications to Windows system files and folders, installation of new software. If the user clicks or taps No, the change won’t be carried out. If the user clicks or taps Yes (and enters the administrator password, if required) the application receives administrative permissions, and it can make the system changes it wants. These permissions are given only until the application stops running, or it is closed by the user. The same goes for files that trigger a UAC prompt. There are four different alert messages that can be associated with User Account Control. They are as follows:

Windows needs your permission to continueA program needs your permission to continueAn unidentified program wants access to your computerThis program has been blocked

Also, there are many changes that require administrative privileges. Depending on how UAC is configured on your Windows computer, they can cause a UAC prompt to show up and request for permission. These are as follows:

Running an app as administratorChanges to system-wide settings or files in the Windows or Program Files foldersInstalling and uninstalling drivers & applicationsViewing or changing another user’s folders and filesAdding or removing user accountsConfiguring Windows UpdateChanging settings to the Windows FirewallChanging UAC settingsChanging a user’s account typeRunning Task SchedulerRestoring backed up system filesChanging the system date and timeConfiguring Parental Controls or Family SafetyInstalling ActiveX controls (in Internet Explorer)Making changes to the registry

UAC blocks elevation of executable applications that are signed with revoked certificates

In Windows 10, new User Account Control (UAC) behavior disallows/blocks the elevation of running applications that use revoked certificates to sign executable binary files. This behavior prevents users from running certain applications. For example, users cannot run applications whose binary files are signed with stolen certificates. According to Microsoft, to run an application, you must have the binaries files signed with valid certificates. Hope this post is clarifying enough! Read: This app has been blocked for your protection message in Windows 11/10.