I got jee main rank 6048 and adv rank 6469. What course should I choose.

Hello dear
First of all congratulations on your results .
You did well and secure a good rank.
According to your Rank you will get definitely a good college.
Course will be depend upon your interest .
If you want core branches than you should opt for nits ( like Allahabad ; Jaipur ; kurukshetra etc.)
But if you are interested in any other non-core branch you can take admission in IITs also.
So you have to choose one thing here ( branch or name )
https://engineering.careers360.com/jee-main-college-predictor
Use this link for more options .
Make a list of the college along with branches in a preference order in which you want to go and can go.
Good luck.