User Account Control (UAC) is a security component in Windows operating systems. UAC enables users to perform common tasks as non-administrators and as administrators without having to switch users, log off, or use Run As.
Since installing some applications on a system requires an administrator access token, a mechanism is in place within the operating system to automatically detect the launch of a setup installer. When an application setup is detected, UAC displays a consent prompt for the user to validate the installation process. Following installation, the application will not require the user to provide consent or credentials, unless it is an administrative application.
The consent prompt is presented when a user attempts to perform a task that requires a user administrative access: 'Do you want to allow the following program to make changes to this computer?'
Click Yes to continue with the task that was initiated.
User Account Control settings (microsoft.com)