Tax free salary means that Estonia doesn't impose taxes on salaries paid offshore.
https://learn.e-resident.gov.ee/hc/en-us/articles/360001761658-Dividends-salary-and-directors-fee
For the purposes of the following guidelines, a director = management board member of the Company.
Estonian rules provide that directors’ fees paid by an Estonian company to a non-resident director are always subject to 20% personal income tax. Tax treaties follow the same logic and normally allocate the taxing rights to the country where the company resides. This means that since the company is established in Estonia, then all directors’ fees are taxed in Estonia, no exceptions.
As director/board member, can you take "normal salary" from Estonian company without paying director's fee?