As a native speaker of English I only translate into my mother tongue in order to provide translations of consistently high quality.
Translators translate the written word, interpreters interpret the spoken word.
The source language is what a translator translates from, and the target language is what they translate into.
You can see my name on the official list published by the French Court of Cassation: https://www.courdecassation.fr/informations_services_6/experts_judiciaires_8700.html. For information, any certified translation carried out by a French court-sworn translator is valid all over France and with foreign authorities.