Windows
Hold Alt and type 3 on the numeric keypad.
Hearts
Copy the character, or use the shortcut that matches your keyboard and app.
Hold Alt and type 3 on the numeric keypad.
Character Viewer → heart
Type 2665 then Alt + X
Insert → Special characters → heart
Click the keycap, then paste with Ctrl+V or Cmd+V.
Num Lock on, hold Alt, type 3, release Alt.
Use the Unicode, HTML, CSS, or JS value below in documents and stylesheets.
U+2665♥♥\2665\u{2665}Alt + 3