You need to understand lighting (three-point lighting), audio (the most underrated part of video), and framing.
It offers asymmetric returns; the downside is low (cost of a phone and time), but the upside can be life-changing financial and personal freedom.
While formal education is not required, having a degree in a related field, such as film, video production, or communications, can be beneficial. Online courses, workshops, and tutorials can also help develop specific skills, such as video editing or cinematography.
For most, 90% of your income will come from 90% of your effort outside of filming—emails to sponsors, editing, and analytics review.