Apple editors were asked questions about text in UX, here the most interesting:

Technical Concepts: give the minimum necessary information, and expand elsewhere

If a lot of text: make the block important, replace with a photo or video

Make text as long as necessary but as short as possible

Push Notifications, check-questions: definitely right now? saves from opening an app? explains something?

Test the text on other people. If there are no people around, read aloud