I got a search hit for "is a holster required when carrying a concealed handgun in Texas."

This is not a question I would have ever thought to ask, but the answer is no.  You just have to keep it concealed.

I knew of someone who once just stuck a snubby inside a velvet Crown Royal bag and carried it around in his hand while grocery shopping.  That's not how I would do it, but it worked just fine for him.