Text extraction

You can use the Localization Dashboard to gather your text for translation.

There’s some information about it here, although it’s somewhat out-of-date now:
https://forums.unrealengine.com/development-discussion/content-creation/34379-localization-dashboard-preview-and-explanation-of-ue4-s-text-localization-process?63394-Localization-Dashboard-preview-and-explanation-of-UE4-s-text-localization-process=#post250553

The dashboard is enabled by default in newer versions, and comes with a default “Game” target. You’ll want to configure that to gather from your assets, add the languages you need, and run a gather.

This will give you your source text, which you can then export to PO to translate (something like PO edit might help here), before importing your translations and compiling them.

You also need to make sure the correct cultures are set to be packaged, as well as making sure your internationalisation support is set correctly (you can find these settings under Project Settings → Packaging).

How to extract all text in my project?
There are hundreds widget in my project,and every one has some default Text widget and direct set text in BluePrint. Now I try to translate them to another language,does it has any solution better than modify every widget by manual?
Thanks a lot;

UE4 has some rudimentary localisation tools:

And here’s some details: