All translate can translate installed themes and modules that support the new translation system introduced in PrestaShop 1.7. Translation options are specified on the control panel. In order to translate into multiple languages, check the Translate into multiple languages checkbox and select desired languages by simultaneously pressing Ctrl button and clicking on their names. Alternatively, if you want to translate a theme/module into all available languages, choose All from the target language drop-down list (it’s the last item).
Please note that although source language can also be specified, in order to be able to translate from a language other than English, your theme/module must be already completely translated into that language. Use this feature only if the default language of the theme/module you are translating is not English.
Overwrite existing translations checkbox controls whether existing translations will be overwritten. Uncheck it to only add missing translations. If this checkbox is activated, All translate will additionally translate names of shop pages and data created by several commonly used built-in PrestaShop modules.
To translate a single theme or module, click the Translate button to the right of its name. You can translate multiple items at once. To do that, check the checkboxes to the left of themes/modules you want to translate, click the Bulk actionsbutton at the bottom of the configuration page and choose Translate selected.