Permits for garage conversion

[Juan Campos]

Hi I am in grand praire Texas, and I was wondering what the process was to close off my father in laws garage and converting it into a room, I've been doing contractor work a little over 6 months now and I've learned a lot, I am confident in building the wall my self, framing, taping bedding, texture, painting ect. 

however I was wondering what the process was to pull permits from the city and if there is anyone on here that can assist  Me with that, and what the cost should be. Thank you all