A site for finding out what cities in Texas are advertising fire department openings is:
This is the state commission on fire protection.

You can click on the links to see what the hiring requirements are for most cities. (They may vary greatly.) But this is not all of the jobs in Texas. Large cities like Dallas or Houston may not be listed here.

You can also read about all of the training curriculum, and more, on this site

Some more info, and links, about Texas FF employment can be found at:

Good luck.