How do I do this
My phone said I need an update
and I can’t put a card on my phone
iPhone 8 Plus, 16
If you are talking about a SIM card, see this Apple article: How to unlock your iPhone for use with a different carrier
How to unlock your iPhone for use with a different carrier - Apple Support
- Apple can't unlock your iPhone for use with a different carrier. Only your carrier can unlock your iPhone.
You need to contact your Carrier.
See also these Apple articles below:
If you see No Service, Searching, or SOS on your iPhone or iPad
If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support
Manually update your carrier settings on your iPhone or iPad
Manually update your carrier settings on your iPhone or iPad - Apple Support
Update your network provider settings manually on your iPhone or iPad
Update your network provider settings manually on your iPhone or iPad – Apple Support (UK)
If you see a Cellular, Ultra Wideband, or Apple Pay Issue message after an iOS update or restart