Q: Is it necessary for Thanaa to be recited in Fardh salaah with jamaat (congregation) if you are not the imam? If yes, should it be recited by a latecomer joining the jamaat and whe:n immediately after the takbeer or when he stands up to complete the missed rakaat/s?
A: Thanaa will be recited by the Imam and Muqtadi (follower). If he has missed Rakaats then he will recite it when he stands up to fulfill the missed Rakaats.
Moulana Yusuf Laher