A short reference note can disappear every time you return to the application where you are working. PowerToys Always On Top lets you pin that window above ordinary windows. It is most useful for a small amount of information that needs frequent checking.

First reduce the reference window to the necessary content. A compact checklist is easier to keep visible than a full document covering half the application. Position it away from Save, Submit and other controls you will need during the task.

Pin the intended window

Enable Always On Top in PowerToys, select the reference window and use the configured activation shortcut. Microsoft's default is Windows+Ctrl+T. If the border indicator is enabled, check that it surrounds the correct window. Then click the work application and confirm the reference remains visible.

Pinning controls stacking order; it does not mean keyboard input will always go to the reference. Before typing, check which application has focus. A simple dry run with harmless text can prevent a note or shortcut from landing in the wrong place during real work.

Keep the exception easy to remove

Select the pinned window and use the same shortcut again to unpin it. Practise that once before relying on the arrangement. If the window unexpectedly covers a dialogue or blocks a control, unpin or move it rather than trying to work around an obscured button.

Microsoft notes that another topmost window can compete with the pinned one, including some remote desktop environments. A window appearing behind such an application does not necessarily mean the shortcut failed. Check the documented compatibility limitations before changing unrelated display settings.

At the end of the task, remove the pin and close any reference containing private information before sharing the screen. If one application should never be pinned, review the utility's exclusion setting. The finished arrangement should make a particular comparison easier while leaving ordinary window behaviour available when the comparison is over.

Source: Microsoft PowerToys documentation.