Windows
Hold Alt and type 224 on the numeric keypad.
Greek
Copy the character, or use the shortcut that matches your keyboard and app.
Hold Alt and type 224 on the numeric keypad.
Character Viewer → alpha
Type 03B1 then Alt + X
Insert → Special characters → alpha
Click the keycap, then paste with Ctrl+V or Cmd+V.
Num Lock on, hold Alt, type 224, release Alt.
Use the Unicode, HTML, CSS, or JS value below in documents and stylesheets.
U+03B1αα\03B1\u{03B1}Alt + 224