Hello Subhashini,

If you want to apply for colleges like NITs,IIITs or GFTIs then first you have to qualify JEE Main cutoff as per your category. Below I have provided 2019 JEE Main cutoff (percentile) category wise - 

• CRL : 89.75
• GEN-EWS : 78.21
• OBC-NCL : 74.31
• SC : 54.01
• ST : 44.33
• PwD : 0.11

So if you have cleared the required cutoff as per your category then you JEE Main qualified. Now to get admission in colleges through JEE Main score, you have to attend the counselling session of the respective institute. For getting admission to NITs,IIITs or GFTIs you have to go for JoSAA counselling. For private collges that accepts JEE score, you have to attend their respective counsellng session. Now there can be hundreds of colleges which can be good for you. To find out which colleges will you be getting as per your JEE Main score, better attend the required counselling session. And, if youn dont get seats in colleges like NITs, IIITs,GFTIs through JoSAA, then you can attend CSAB counselling which will begin after JoSAA ends. 

You can go through this link and checkout the details of JoSAA counselling : https://engineering.careers360.com/articles/josaa-counselling

Also, visit this link to get the detailed information regarding CSAB counselling : https://engineering.careers360.com/articles/csab

Hope that you get a good college of your choice. Good Luck !!!