Windows 11 devices RSAT tools can be added using the Optional Feature menu options.
Click the Start menu and in the search box, type Optional Features and launch it. You can also launch the optional features by going to Settings > Apps > Optional Features.
In the Optional Features window, seek the option Add an Optional Feature and click View Features.
In the Add an Optional Feature window, search for Active Directory Users Computers and press the enter key.
Select RSAT: Active Directory Users Computers and click Next.