iPhone 14 and sim not working

SmartyTrousers is correct, the US version of the iPhone 14 is eSIM only. 

Versions of the iPhone 14 on sale outside the US support both physical SIM and eSIM.

Presumably, you have the US version of the iPhone 14, so you won’t be able to use Smarty, as they don’t currently offer eSIM. In fact, the only UK networks offering eSIM are Vodafone, O2 , EE and relatively new eSIM compatible LycaMobile. 

With the exception of LycaMobile, the other networks only offer eSIM to long term monthly contract customers, not pay as you go customers. You would be able to get a SIM only deal from them, probably for a minimum duration of 1 year.

The other complication you have is that, with the exception of LycaMobile and Vodafone, you obtain an eSIM via a “SIM swap”, meaning you are given a physical SIM first, which the network then swaps to an eSIM….Hopefully, networks’ stores make this a five minute job. 

During a recent trip to Arizona, I bought a new iPhone 13 mini, eschewing the offered iPhone 14 range by staff in the Apple Store in Scottsdale, precisely because the US variants of the iPhone 14 are eSIM only.

Also, supposedly, Apple make it easy and simple to transfer eSIMs between iPhones, with eSIMs just transferring from one phone to another. Not in my experience if you look at the attached screenshot. 

Whilst some people stateside are happy with an eSIM only iPhone 14, a considerable amount of people actually bought the phone through Canadian distributors, as the iPhone 14 on sale in Canada does have physical SIM and eSIM capabilities.