xxgingerstarxx Hi there,
Thank you for contacting the giffgaff Community. Hopefully the following information will help to assist you further.
Your iPad would need to not be Locked to any Network in order to work with giffgaff!
All giffgaff SIMs are 3-in-1 so you should be able to snap out the size you require for your device!
The video below explains in detail how to use the 3-in-1 SIMs supplied by giffgaff:
You can request a new SIM from https://giffgaff.com/free-sim-cards. Once received just setup your giffgaff Account an Activate the SIM with either £10 Minimum Airtime Credit or £6 Goodybag!