Windows: hold Alt and type 0176 on the numeric keypad
Mac: press Option + Shift + 8
Chromebook: press Ctrl + Shift + U, type 00B0, then press Enter
iPhone or iPad: press and hold 0, then select °
Android: press and hold 0, then select °
Linux: press Ctrl + Shift + U, type 00B0, then press Enter
Copy and paste this symbol: °