What are ‘fresh noodles’ in a salad

Fresh - as opposed to dried.

Specifically in the UK, 'noodles' can only be Chinese/South-East Asian. Pasta is pasta, it is never called noodles over here, so we don't have the confusion the US has with the term.*

Fresh noodles you can find in the supermarket, usually refrigerated slightly, in with the 'delicate veg' section - near mangetout, pak choi, beansprouts, chillies etc.

There are usually a minimum of three types, The one you want will be just labelled 'Chinese noodles'^[1] [pretty much the same as fresh spaghetti, made of durum wheat but has been through a fermentation phase giving a darker yellow/brown colour & stronger flavour, then tossed in oil to prevent sticking] alternatively, rice noodles [usually very skinny, vermicelli, very white, less oil] & then the bright yellow, pre-flavoured, Singapore noodles [again rice vermicelli but with 'flavourings' (avoid;)]

If you can't find them in the fridge in your store, then second best is 'vac-packed' which will be near the 'insta-food' sauces - [pad thai in a bag, just add chicken] type of things. These are similar to fresh, often with monikers like "straight to wok" etc. They're nowhere near as nice as fresh & always look to me more Japanese than Chinese, as they're quite white by comparison, so possibly not fermented].

If you can't get either of those, then it's back to dried. Soak in hot water 5 minutes, stir-fry.

Sometimes, I actually prefer dried. It depends on what I'm making.

The difference is very similar [unsurprisingly] to fresh vs dried Italian pasta. Some dishes are OK using dried, some have got to be fresh. Fresh doesn't have the bite, or al-dente that dried has. Just the same with noodles, except the 'bite' can often be slightly more rubbery [not in a bad way] compared to pasta.

One additional tip - you can pretty much pick the strength of flavour in dried noodles just by the colour. The browner they are the stronger the flavour [assuming no-one cheated & put colourings in them.]

If you're really really stuck, ramen noodles are very close to 'Chinese noodles' but only if they're good ones. Most ramen in cheap foil packs you can't see what's in it until you open it. Avoid unless desperate ;)

*^{Just to keep a balance, we have many other things we can get linguistically confused over… coriander, chili, to name but two ;)}

^[1] After comments, it's quite likely that these would be called 'chow mein' noodles in the US.