The answer to 'how to fix bathtub' is to first identify the specific issue, such as a leaky faucet, clogged drain, or damaged surface. For minor problems, you may be able to make simple repairs yourself. However, for more complex issues or if you're not confident in your plumbing skills, it's best to call a professional plumber.
If the problem is a leaky faucet, you can try replacing the washers or O-rings. Shut off the water supply, disassemble the faucet, and replace the worn parts. For a clogged drain, use a plunger or drain snake to clear the blockage. Avoid using harsh chemical drain cleaners, as they can damage the pipes. If the bathtub surface is cracked or chipped, you may need to refinish or replace the tub.