Why doesn't my new phone have any mobile data?

[RebW]

I received a new Samsung Galaxy and set it all up at home. All seemed fine. However, when I left the house today it became clear that I had no 4g/5g and therefore no mobile data. Therefore no roaming wifi access. I cannot work out why

[Enlli]

Could do with more information.

Did this come with a new SIM card?

Have you checked in the settings that mobile data is actually turned on?