Hello student some of the major courses in interior design after 12 are mentioned below :-

BAInterior Design- Duration is 3 years.

Bachelor of ArchitectureInterior Design- Duration is 5 years.

Bachelor ofInterior Design- Duration is 5 years (CEPTcourse)

BAInteriorArchitecture andDesign- Duration is 3 years.

Bachelor ofDesign(B.Des.)

BScInterior Design- Duration is 3 years.

You need to appear in NATA(National Aptitude Test in Architecture) and jee paper 2 for barch to get admission in top architecture college.

Eligibility criteria for jee main paper 2 and nata is student must be appearing or pass in 12 with Physics Chemistry and Maths as main subjects with English.

Feel free to comment if you have any doubt

Good luck