The hot water in my shower will not cut off. I turn the knob until it is closed all the way, but the water still will not shut off. How do I fix this? Is the knob stripped on the threads and just need to replace the knob, or is it a bigger issue?

Thanks

Before we can help we need to know the brand name of the faucet, the type, one handle or two knobs and how old it is. Regards, Tom

Yes, there will normally be some valve, washer, or other item that actually shuts the water off,

Since you are talking threads I will guess you have a knob that turns, and as you tighten it, the water stops, if this is the case normally there is a washer that can be replaced unless there is damage to the seat where the washer sits.

You will have to shut the water off to the shower and take it apart, places in the US like home depo and Lowe's normally have information and parts.
If you take your brand and model to the store they may be able to help you.