If your entire yearly turnover is less than 8,000,000 RSD, then no, you don't.
If you do not compute VAT for the sale of goods and services, you do not have the right to deduct prior taxes, you are not required to keep the records required by the VAT Law, and you are not permitted to indicate VAT in invoices.
You may elect to pay VAT if your revenue is less than 8,000,000 RSD, nevertheless.
Therefore, when your annual sales is less than 8,000,000 RSD, this is an option rather than a requirement.