Windows: hold `Alt` and type `0153` on the numeric keypad
Mac: press `Option` + `2`
iPhone/iPad: type `TM` and use the trademark symbol suggestion, or copy `™`
Android: long-press `T` or use the symbol keyboard to find `™`
Copy and paste this symbol: `™`
HTML: use `™` or `™`
Unicode: `U+2122`