Is TCS will send the employee in PIP on the basis 6 month performance. What to do resign or else go on PIP?

Depends on the project bro if you're maintaining the same level of performance even after 6 months you would be either put in PIP or be released from the project...And in case If you are in PIP where as per my knowledge, i think you would be given a chance rectify your mistake but if you are still repeating the same would be asked to resign at the end..

Resignation bro