Incomes
Finance → Incomes lists every amount that came into the company, its reason and the account it went into, and lets you record income that doesn't come from a sale.
This article is still being written: it explains what the screen is for, and its steps are not written yet.
The Incomes page gathers all the money that came into the company: what came from cash sales and installment collections, and what you record by hand with New income, such as money you got back or income unrelated to selling. Each income shows its source and the account it went into.
You'll find it in the sidebar under Finance → Incomes. Owners and managers can open it, and so can anyone given a role with the finance management permission.