US Tax implications of buying a car

My husband and I are starting the process of buying a car in the UK. As I've never bought a car here before I'm just wondering if we use both of our salaries and we are both on the car loan does that need to be reported on my US taxes and how would we do that? Thanks.

No - absolutely no US impact, unless you get some really fringe edge case (e.g. you buy a classic car that appreciates in value and you've got a capital gain when you sell it). A standard depreciating car with a standard loan has no impact on US (or UK) taxes.

There could be an edge case similar to a mortgage, where exchange rates could cause a phantom gain - but a car loan is too small for that to matter unless you had a huge loan and/or really drastic changes in exchange rates. And it'd only matter if you sold the car before paying off the loan, so there was a lump sum "gain" - pay it off over time and there's no chance.