According to Hannes Udde, senior specialist at the MTA's Service Department, it is worth reviewing one's pre-filled data in the E-Tax/E-Customs portal to ensure that everything is correct when they submit their return.

"If any data in your tax return preview is missing or differs from what you know, please contact the payment debtor or recipient of the expense and ask them to submit the missing data to the tax authority electronically or correct their submitted data," Udde said.

"It is important to note that holders of investment accounts must submit all of their information regarding their transactions from their bank to the MTA themselves," he added.

If any employers, educational and training institutions or other institutions are unable to submit or correct their data electronically, those filing will have to correct said data on their own returns as well as submit supporting documentation. Data on loan interest payments may continue to be submitted electronically via filers' online banks; this does not include interest paid on student loan payments. Clients can request additional information regarding interest payments from their bank.

Users can contact the MTA with any questions regarding their tax returns via email at eraklient@emta.ee or in the E-Tax/E-Customs portal.