Taraweeh prayers are sunnah prayers in which many rakats are performed.
Performing Taraweeh with faith and hope pardons past sins
Prophet Muhammad (ﷺ) said, “Whosoever performs Tarawih prayers at night during the month of Ramadan, with Faith and in the hope of receiving Allah’s reward, will have his past sins forgiven.”Riyad as-Salihin
Performing Taraweeh is encouraged, however it is not obligatory
The Messenger of Allah (ﷺ) used to urge (the people) to perform (optional Tarawih) prayer at night during the month of Ramadan. He did not order them or make it obligatory on them.Riyad as-Salihin
Performing Taraweeh in masjid is not compulsory, it may be performed at home
Allah’s Messenger (ﷺ) made a small room (with a palm leaf mat). Allah’s Messenger (ﷺ) came out (of his house) and prayed in it. Some men came and joined him in his prayer. Then again the next night they came for the prayer, but Allah’s Messenger (ﷺ) delayed and did not come out to them. So they raised their voices and knocked the door with small stones (to draw his attention). He came out to them in a state of anger, saying, “You are still insisting (on your deed, i.e. Tarawih prayer in the mosque) that I thought that this prayer (Tarawih) might become obligatory on you. So you people, offer this prayer at your homes, for the best prayer of a person is the one which he offers at home, except the compulsory (congregational) prayer.”Sahih al-Bukhari