Hello Akash!
In order to get information about the cutoff marks on which you can get admissions in IITs in Jee mains/ advance you need to study the previous year cutoffs and estimated cutoffs for the exam. You can get the full details about the same in the link provided below. Hope this helps.

https://www.google.com/amp/s/engineering.careers360.com/articles/jee-advanced-cutoff/amp

All the best.