You can find this page in the Shop settings menu. The translation section is the place where you can translate your shop’s admin and/or front end into other languages different than your default one. When you first enter the page you need to choose what part of the shop you are going to translate and then have to select the language you’re going to make translations. Then click on edit and you will see all pages that need translations. There is a search if you’re looking for something specific, too. When you choose the page for translation you see the word/phrase in your default language and next to it there is a field where you write the translation. When you are ready click save and continue your work.