No. Some work needs a permit or a licensed plumber under local rules, and each provider decides what they offer. Describe the job when you book so your provider can tell you whether it is something they take on.

Turn off the valve under the fixture or the main shut off if the leak is steady, and put a bucket or towel under it. Tell your provider what you have done when you book.

Your provider publishes their rate and confirms the price with you before starting. If the cause turns out to be bigger than described, your provider will tell you before going further.