Dear Aspirant 

First of all Congratulating you on your admission in your new school and I would like to tell you that tc can be abbreviated as transfer certificates that means when you visit your old school and ask for transfer certificate they will give you certificate duly signed by school principal which conveys that you have been transfered from current school and are eligible for taking admissions anywhere else. So you have to submit same certificate to your new school. 

Good luck for your future :) 

Feel free to ask if you have any further queries.