Windows: hold Alt and type 0241 for ñ or 0209 for Ñ
Mac: press Option + n, then n for ñ or Shift + Option + n, then N for Ñ
iPhone/iPad: press and hold n, then select ñ
Android: press and hold n, then select ñ
Linux: use the compose key or type Ctrl + Shift + u, then 00f1, then Enter for ñ
Spanish keyboard: press the dedicated ñ key
Copy and paste: ñ or Ñ