You must keep the original of the Affidavit in a safe place and make one copy for yourself.
So that the original can be kept safely stored, it is a good idea to certify the copies. This means that a copy is confirmed by a qualified person - usually a solicitor - as a true copy of the original document. The solicitor who swears your Affidavit for you might be able to help you with this. While Rocket Lawyer does not provide certification services, they can be provided by most solicitors for a fee.
Provide a certified copy of your Affidavit to those who need a copy.