If they are free NHS hearing aids there will be a tube from the aid which hides behind your ear they are a fiddle to put on at first but easier to adjust tone and volume and if you wear your hair long won't be seen.
If they are private "in the ear" they are less visible" , but, fiddly, difficult to adjust, small batteries have a short life and prone to getting lost or eaten by the dog ( expensive it did happen).
Both types are fine for normal conversation and daily routine, neither are any use in a noisy environment, pub, cocktail party, loud music. If noise is very loud they will overload and shriek, take them out.