Thanks for Reaching out to us.
I would request you to kindly add the Loupe tool in your main toolbar. thats how you can do that
1) launch any pdf and right click on the main toolbar
2) select “Show Select and zoom Tool” and click on “Loupe Tool”
3) click on the loupe tool icon added to the toolbar and then click on any area in the pdf
Now you can see an enlarged view of a specific area in a pdf in a separate window
Let me know if that solves your concerns
Ayush Jainrhtgg commented
No such tool in adobe digital content reader on android. Suggestions?