The answers you’ve received so far are pretty good. I don’t know about OFM franciscans, though I imagine its similar to the Capuchins. With Capuchin Franciscans, every friar is a brother, but some of the brothers are also priests. In fact the majority are priests, but there are quite a few lay brothers (non-priest friars) as well.
All you really need to enter the order is a high school diploma, but formation includes: 1 year of Postulancy + 1 year of Novitiate + post-novitiate studies. Post-novitiate is more variable. Those that want to be priests go on for 5-6 more years of theology and philosophy studies. Those that do not want to be priests will go on to study other things, like get a bachelor degree if you don’t already have one, a masters degree such as a master of divinity, master of social work, maybe a degree in nursing, counciling, education, psychology or wherever the Order and the Lord are calling you to ministry. A few go on for PhD’s and pontifical degrees. So…for a priest candidate that would come to about 7-8 years of formation if you already have a bachelors degree, about 10 years if you do not. Most lay brothers are in school for less time, but not necessarily. You usually take final vows around the 6 year mark though.