GAP year - You apply late or get accepted and then ask for a GAP year?

Applying to College
1

I want to take GAP year but where do mention that when applying?
Or you get accepted and then ask for a GAP year?

2 
                 Get accepted and then ask for a deferral, but make sure the financials work out, if there is scholarship money at play. Do not assume a scholarship is deferrable even if your admission is.
3

Also some colleges will not allow you to defer (UC’s and Cal States). You would have to reapply again or wait to originally apply after your Gap year.

Check each schools deferral policy.