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, then select ©
On Android, press and hold the letter C, then select ©
In HTML, use © or ©
In Microsoft Word, type (c) and let AutoCorrect convert it, or insert © from Symbols
In Google Docs, use Insert > Special characters and search for copyright
Copy and paste this symbol: ©