With an annuity scheme, the borrower makes the same payment each month. The proportion within the payment changes: at the beginning of the term, most of it covers interest with only a small portion reducing the principal debt, while closer to the end it's the opposite.
An alternative is a differentiated payment, where the principal is repaid in equal installments and interest is calculated on the remaining balance. In this case, the first payments are noticeably higher, but the total overpayment over the entire period is lower.
A practical consequence of annuity: early repayment is most beneficial in the first third of the term, while payments are dominated by interest. Closer to the end of the term, the principal is already almost fully repaid, and early repayment saves little. When comparing bank offers, focus not on the monthly payment amount, but on the total cost of credit.