Degree

Yes, you can apply for the UPSC exams in 2019, once you have graduated or even if you are awaiting results. The only condition is that you will have to submit proof of graduation once you have completed the course and will also have to submit detailed application form for UPSC (Main) examination.

Hi Sujana Peram,
You will require a bachelor's degree to be eligible to study a Master's degree anywhere in the world. You can enroll in a bachelor degree course after your diploma not a MS.

Hi Aryan,
It is not necessary to pursue Diploma before degree course. You can directly apply for Hotel Management degree from any recognised university.
Regards.

No, there is no entrance exam for this course. Admission is based on the percentage in 12th.

Please check for your eligibility to pursue M. Des from the criteria mentioned at the link provided below:
Master of Design (M. Des. ): Eligibility:
The eligibility to pursue Master of Design, one need to have a Bachelor of Design or Bachelor of Architecture degree with a minimum of 50% marks. There are several universities which are offering Master of Design from distance learning also. Their list is as followed:
Amity University, Noida
Aesthetic College of Interior Designing, Calicut, Kerala
Delhi Institute of Technology and Paramedical Sciences, New Delhi
Regards.