Engineering

You can get any state private engineering college by this percentile.

Your rank is very good you can get the good NIT. Please use college predictor for best information-
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

Yes, you will get middle or lower order nits like NIT Patna, NIT Jalandhar, NIT Jamshedpur, NIT Durgapur, IIITs. You can predict other possible colleges here:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

Yes, you can find EC branch and maybe CS in NIT at 940 rank because you belong to PWD.

Your academics are very low so you cannot get a good university in USA.

Hi,
Yes, you will get a seat in mechanical engineering with this score in Ernaculam. You should apply for this college. In first round itself, you will get a seat.

There is no meaning of marks. Your rank should be under 2000 to get this branch.

I would suggest you to use the college predictor tool which will list the colleges you are eligible to apply and the courses available.
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

For admission in IITs you need to appear for JEE Advanced and if you score less than 10k rank you will be eligible to take admission. With this percentile, it's not possible for you to get admission in NITs. It is better for you to go with private institutes. Use the JEE college predictor tool in order to know the colleges where you can get admission.

As per your rank in JEE Mains, it will be difficult for you to get admission in IIIT Pune. Still, you should give a try. You may get a seat in the last round. You can predict other possible colleges here:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor