Hi,
I'm Sumit, here to answer your query at the Microsoft Community.
Apologies for any inconvenience you are experiencing. I am happy to help you today.
I'm sorry, but to be honest, Microsoft Edge on the phone does not have the capability to read PDFs yet. It is possible only with the PC version.
To request a feature functionality, feel free to share your feedback with Microsoft. Just a heads-up, this forum is a space where users help each other out, and it’s not directly affiliated with Microsoft. You can send Feedback from the Android Edge from Menu > Feedback.
Hope that helps, and rely on us for any further inquiries. All the best.