Can’t see the words on the screen, how do I make them bigger?

Here is one way.

Magnify nearby objects with Magnifier on iPhone - Apple Support

Here are additional ideas.

iPhone & iPad Accessibility Support - Official Apple Support

If you haven’t already, activate zoom mode for your iDevice. This makes all the screen content larger.

On any iOS before the 13 Beta:

For increasing the size of text only, go to Settings -> General -> Accessibility -> Larger Text. Drag the slider further right to increase the text size across all apps.

Theo

[Edited by Moderator]