Quick Assist

Windows 11 includes a remote assistance app called Quick Assist that lets one user share their screen interactively with another user so that they can troubleshoot and help solve problems they might be experiencing.
Obviously, both of the PCs used with Quick Assist need to be connected to the Internet. Less obviously, the person proving assistance---the helper---must have a Microsoft account, while the sharer---the person being helped---does not.
To get started, both parties should be in communication with each other using their phones or a communications app. And both should open Quick Assist on their PCs.

Oddly, Quick Assist does not appear in the Start menu, but you can find it easily enough with Search.
Next, the helper will click "Assist another person" and, if this is the first time they've used Quick Assist, they will be asked to sign in to their Microsoft account. Quick Assist then generates a short security code that the helper must give to the sharer.

The security code expires in 10 minutes. The helper will see a countdown in Quick Assist, and a new code will be generated every 10 minutes.
Now, the sharer can enter the security code in Quick Assist and click the "Share screen" button to begin the quick assistance session.

Once the connection is made, the helper will be prompted with a choice to either take full control of the sharer's PC, or to just view their screen without taking control.

What you choose here is based on the type of help being provided and whether the sharer is technical enough to take the troubleshooting steps given by the helper. If you are more technical than the sharer and would like to simply solve the problem, choose "Take full control. But if the sharer simply wants to show you something, choose "View screen."

Either way, the sharer will need to click a final "Allow" button to make the connection.
The most important thing to remember here is that the sharer is always in control: they can easily disconnect the helper at any time. So there's little to fear from giving someone---especially someone you know and trust---full control of your PC.
The sharer's desktop will appear in the Quick Assist window on the helper's PC.

And on the sharer's PC, the Quick Assist window now displays in a minimal view, noting that screen sharing is on, and the Desktop has a yellow border.

To disconnect the remote connection at any time, click the "Pause" button.
Take full control of a sharer's PC
In full control mode, the helper can interact with the sharer's desktop remotely. These interactions are normal: the helper can now interact with the remote PC normally using their keyboard and mouse/touchpad. But the remote cursor is much larger than usual for easier use.

The helper can also access the following capabilities in Quick Assist using the buttons in the toolbar:

Select Monitor. Quick Assist can only display one remote screen at a time. If the sharer has multiple monit...