Hi and Welcome to the forum.
It's not quite clear what the issue is so ill explain a few things and I hope it helps.
If not just let us know and we'll try again.
Where did you buy the iPhone from ?
Is it locked to the Vodaphone Network and you want to use it on another network. If so you'll need to ask the original owner / Vodaphone Customer to ask them to unlock the iPhone by them filling out the online unlocking form. Only this person can request this.
If the phone is locked to Vodaphone but you want to use a Vodaphone SIM card and it's showing as no service then you may need to check it's not been IMEI blocked by the network which is usually applied die to loss / theft and or insurance claim.
One of the useful sites is
http://www.checkmend.com/uk/ to check its status.
The iPhone also has an activation lock which stops another person using another SIM card in it so the original owner needs to de activate t is via using their Apple ID before it'll accept any other SIM card.
help link on this
https://support.apple.com/kb/PH13695?locale=en_GB help link about iCloud is
http://www.apple.com/uk/support/icloud/
Current Phone >
Samsung Galaxy s²⁴ Ultra 512gb.