Would it be okay to put a Vodafone SIM card into a new Iphone X?

I'm thinking about buying a sim free Iphone x then putting my current vodafone sim card into it. Would this cause any problems or eould it be okay? Id have to buy a new SIM card contract the year after, but I don't mind having to do that.

In most cases, you just put your SIM card in and it'll work - you might have to request a couple of server settings to get SMS texts up and running properly but you can do that using Vodafone's automated services. You would not have to commit to any new service contract, your SIM would be on the same service as before.

*It may be worthwhile committing to a new service though, one that is SIM only, because otherwise, you can end up paying for your previous phone even though you've paid it off!

Probably

As Crim Liar says. If you want to keep your old SIM card to keep your phone number, then you can still swap SIM cards and network. See your provider. Changing network is called porting your number and is free in most countries.

That's perfectly fine. That's sort of the point of those models being sold.