If you have not paid enough tax in 2018, you can request for an additional prepayment and pay it in MyTax. By paying an additional prepayment you can avoid having to pay back taxes and late-payment interest with relief.
Additional prepayment has replaced the supplementary prepayment, which is why you should not enter any old supplementary prepayment information when paying.
To stop receiving paper-printed correspondence from public authorities, visit suomi.fi/messages to switch to e-messaging. After this, you will receive an e-mail as well as an e-message via Suomi.fi whenever a new tax card, tax return, or other correspondence has arrived to you in MyTax.