Holistic forma – drops, farming, usage, history in Warframe
Forma is one of the most ingenious things in Warframe. You can go through the entire star chart without ever using forma. But once you want to go further into sorties, Eidolon hunts or ESO/arbitrations you need to put forma on your weapons, companions and frames.
Forma is needed if you want to play seriously after completing all story missions. Only invested players will need it; and they will need lots of it. And because of its long build time of 24 hours you either have to come back daily and populate the servers. Or you buy it from the market with platinum and thereby support the game development with money.
What does forma do?
Every rank 30 weapon, companion or warframe can change the polarity of one mod slot by investing one forma. Forma is one time use and using forma will reset the weapon, companion or warframe back to rank 0. In order to change the polarity of another (or the same) mod slot you will need to level up to rank 30 again. Every slot – including stance and exilus – can be changed. Only umbra polarity cannot be created with forma.