The default keyboard shortcut to pin any window to the screen is Windows Key + Control + T. (You can change this, if you want, in the Always On Top section of the PowerToys app.

While Windows 11 already lets you pin apps to the taskbar by dragging-and-dropping icons from the Desktop or the Start menu, Microsoft is testing a new option: dragging-and-dropping from search ...

You can pin chats on Signal so that your frequently visited conversations remain at the top of the screen for easy access.