There is no big difference but you can check this blog it has a really good video explanation: https://www.krisamerikos.com/blog/suggest-offer-propose

There is no real difference. The usage is different depending on the subject involved. The only way to know this is to see examples repeatedly. The meanings are the same however. One example that is always proposal is marriage. I proposed to my fiancee. Marriage proposal, we never use proposition for this.

That depends a lot on context! In terms of something one person makes to another person, a proposal is an offer of marriage, and a proposition is an offer of sex. ;) In business terms, they are more similar. In general a proposition is something simpler, and less complicated. So - typically, a proposal might be made on paper, with a contract, and a proposition might be made verbally, with a handshake.