Copy window between multiple Spaces in Mission Control?
You can't get one window of an app to follow you to all Spaces - but you can, if you have shortcut keys setup to swap Spaces, grab the menu bar of the required window, hit the shortcut &amp; 'take it with you' to the new Space.

If you don't have it set up already, System Prefs > Keyboard > Shortcuts…


One thing to note - if you do that with Finder windows, it can break the 'click desktop to go back to Space 1' functionality, til you relaunch the Finder.