Dear Ms Vibha,
Generally, when you apply for any trademark application on behalf of your client along with POA on Form TM-48 in your favour by your client, the trademark registry will allot you an agent no and the party or applicant will be given an proprietor code.
However, you can also apply for registration as a trademark agent on a form TMA-1 for the same under rule 153. The form is awailable on website of trademark registry.
Advocate and Tradmeark Attorney