From SCP: Secret Laboratory Public Beta Official Wiki

This Template is used to represent key presses on a keyboard, and can also be used to represent mouse clicks.
Simply type the template name, then press | then hit the key you want to show.
{{Key Press|E}} gives E

You can insert multiple keys like shown {{Key Press|W|A|S|D}} to get W+A+S+D

If you want to have multiple keys without addition signs in between them, then add chain= at the end. {{Key Press|W|A|S|D|chain=}} WASD

Certain keys will show up as symbols, or have symbols next to them. like {{Key Press|Shift}} and {{Key Press|Up|Down|Left|Right|chain=}}

Shift

Left Click.png Left Click

Right Click.png Right Click

Middle Click.png Middle  Click

Alt