Hey Tipu,

First of all congratulations for successfully clearing the Reputed JEE MAIN EXAM

The seat allotment in GFTIs (Government Funded Technical Institutes) is done by JoSAA based on the marks obtained in JEE MAINS. The process of seat allotment in IIITs and NITs on JEE MAINS Score is also done by JoSAA, which includes all activites from document verification to final admission into the colleges. 80.5 percentile is not a very good score to be fair, compared to the competition and the number of students appearing each year, but it is still a decent score for getting some good colleges. You might not get a good IIIT or NIT seat based on your score, but you have chances in State Government colleges and you should apply for it if you are interested.

All The Best!!