There's no way I could go back to using just one monitor for work. A couple of quick tips for those that have just started using more than one!
1. Windows+Shift+left or right arrow - holding these keys down will move the currently active window to the monitor to your left or right.
2. Powertoys - Fancy Zones - Fancy zones is part of a Microsoft developed set of tools called 'PowerToys'. It let's you break your monitor(s) into virtual monitors. So you can easily snap a Window into part of your screen. I use it most when I'm on a Zoom call. I have the camera view in one corner of my screen, and I have 2 other areas for viewing the presentation and researching/slacking off.
Kevin Stratvert has a good walkthrough of PowerToys, and specifically the Fancy Zones feature here.
Quick Tips: Multiple Monitors