If you're referring to the function keys (F1 - F12 on most keyboards), then look at /help Function Keys
Function Key support
You can redefine function keys to perform certain commands, just like aliases. For example:
/F1 /say Hello!
/sF2 /query $1
/cF3 /ctcp $1 version
The s and c prefixes for Shift key and Control key respectively.
Note: A function key will behave differently depending on the window in which it is used. For example, when using it in a query window the $1 parameter refers to the selected users nickname. If you're on a channel and the nickname listbox is active then the function key will work on the selected nicknames. If the listbox is not active, the function key will just work on the channel.
If this isn't what you're referring to, then please clarify what keys you are referring to (and/or give an example)