Should I remove my SIM card from old phone before trade in
How do I remove SIM card and card I use it on my new IPad
Question marked as
It is recommended you remove your SIM card before sending your iPhone in. This will tell you how to do that --> Remove or switch the SIM card in your iPhone - Apple Support
Whether it will work in your iPad, you'd need to ask your carrier. The newest iPads may not have a SIM Card slot as they instead support eSim technology. This link explains how to set up cellular service on an iPad --> Set up cellular service on iPad (Wi-Fi + Cellular models) - Apple Support