Hi! The more docs you send the better, passaports, birth certificate, ID from the country the kids are from, rent, info about guardians, proof of schooling, visas if any, negative criminal records...(I think it’s not complicated to find online even if the kid is a minor) things like that. Don’t forget to add info about the petitioner also or the person filling. Also 3 passaport style pics of every kid and petitioner. Hope it helps! 😊

for i-130 you need to submit birth certificate of your child, any religious certificate if you have, family pictures, school record with your name on it if you don't have no worries it's optional. for the petitioner, you need to submit birth certificate, passport bio page, i.d, if you become a u.s citizen you need a naturalization certificate, for other additional documents is your proof is like family pictures like I mentioned above, remittance, chat logs/ video call but this is optional. good luck