Diploma

The fee is depend on the institute every institute have there own fee criteria the fee for this course is start from 35,000 and reach to 3,00,000.

Yes, you can join this course.

Yes, of course you can do Diploma after class 10th clearing ITI. All colleges doesn't have the age boundary. The minimum criteria for admission in Diploma is 10th or equivalent passed. You can also apply for the government. Colleges of your state. If there is some age limit in government. Institution of your state then you better go for private ones. Good luck.

Yes, you can pursue Diploma after class 12th.

You can refer the following link to get detailed information about some of the colleges that offer PG Diploma in interior designing
https://www.shiksha.com/design/interior-design/colleges/diploma-courses-india

*Veermata Jijabai Technological Institute - Mumbai, Maharashtra
*Mahatma Gandhi Mission - Mumbai, Maharashtra
*College of Engineering - Pune, Maharashtra
*Indian Institute of Technology - Mumbai, Maharashtra
*Vishwakarma Institute of Technology - Pune, Maharashtra
*K. J. Somaiya Polytechnic - Mumbai, Maharashtra
*Padmabhushan Vasantdada Path Pratishthan College of Engineering
Mumbai, Maharashtra
I hope it is useful for you.

Of course, 100+ Diploma courses are available all over. Can you please be specific what kind of course you want and which University (if any specific) or your locality, so that I can help you?

Kindly visit this link:
https://www.shiksha.com/law/colleges/cyber-law-colleges-mumbai-all

The admissions will start in January.