On Windows, hold Alt and type 0169 on the numeric keypad
On Mac, press Option + G
On iPhone or iPad, press and hold the letter C on the keyboard and select ©, or use the symbol keyboard
On Android, press and hold the letter C on the keyboard and select ©, or use the symbols menu
In HTML, use © or ©
In Unicode, use © or U+00A9
Copy and paste this symbol: ©