Delete it, or file it away
Do it now (if less than a two minute action, automatically do it then and there)
Do it later
Decide it doesn’t need an action, but file it for reference or future use
Delegate it for someone else to do
Defer the decision about whether the action needs doing to a later stage (usually by adding to your calendar)
Decide there is no action from you, but that you want to track whether someone else follows through.