Natwest mortgage pay solicitor fees

I will be getting a mortgage with natwest. One of the people on the phone said you can include the solicitor fees in the mortgage.

I spoke to a solicitor who said I still have to pay them the solicitor fees, so how does natwest pay your solicitor fees? Do they just put that money into your current account on exchange date?

I did call natwest and asked but the person who I spoke to was new and didn't know and asked to call back a later date.