What is the best way to draw up an agreement with a partner?

Recently (yesterday, to be precise) I began work on one personal project, which, in my opinion, has great potential. Since money (as it often happens) for that part of the project that I myself can’t carry out is completely not pulled out, a need arose for a partner who would agree to work first for an idea and then for a share. And, accordingly, a question came up - you can, of course, agree “in a friendly way”, but, reading the publications on this topic in Habré, I realized that it’s better to somehow arrange the relationship.
The question is how ? A big request from experienced people for advice on how to be


PS By the way, are there by any chance artists who can draw icons? ;) Not for the site and not for the application, but, let's say, some abstract icons. If you suddenly find an interested person, you are welcome to drop something in private.
PPS Turbomilk is, of course, cool, but ...