Dan,
When you make a sell you make a profit/loss, no matter where the money are located.
In Romania:
For all the profit/loss made in the period 01.01.2020 - 31.12.2020 you need to declare to the tax authorities until end of March next year. In 2021 they extended it to May.
If you are not sure how to fill in the tax declaration I would advise contacting an accountant.