How to apply for addition of class of vehicle in my existing Driving License

Any citizen who wants to add a category of vehicles in their license must take the following steps 
Steps to follow for Additional Endorsement in License (Flow may be differ from state to state):- 
1. Visit https://sarathi.parivahan.gov.in/ 
2. Proceed for License related services 
3. Select concerned state 
4. Click on "Application for New Learners License" from "Learner's License" menu 
5. Select "Applicant holds Driving License, Enter DL Number"; fill your Driving License number and Date of Birth 
6. Fill up Application Form 
7. Take appointment 
8. Visit RTO on scheduled date, with original documents