Tap+hold+drag a drawing (tap additional drawings to add more to your selection) to the side of your project to switch to the next one, then drop it in.

Tap+hold+drag to select a drawing, then open the project dropdown menu in the status bar and drag your drawings into the new project there.

If you’re moving drawings to a new app (like Files), tap+hold+drag your drawing(s), open the new app from the control bar or by double-tapping your home button to show all the active apps on your device, and choose the new app. Release your selection in the new app.