I did mine via Thai post. That was with the US Embassy in BKK. Not sure where you are from but if a yank it’s really easy. I did it all from the village and it took less than 2 weeks from when it left my hand until I had it back here.
Good advice above but what I would add is be sure to ask the immigration you will work with directly. I have seen that the Jomtien office requires things that the Ubon office does not. Best advice possible is go in and ask them directly what they require.