Unwanted pdf rotation

[#1]

Prior to using this app I uploaded images as PDFs via the iPhone files app. However, many of my photos got rotated sideways. I think it's due to the distance I take the photo from/ how close the words are. I was hoping that there is a way to lock rotation on this app without buying the paid version. Or, if this app doesn't really create unwanted rotations in the first place. Thanks in advance for your help!

[#2]

Acrobat Reader will display what is in PDF file.

[#3]

That seems more like a document structure issue.

Have you tried using Adobe Reader DC and compare how these images open ?

Or have you used Acrobat Pro DC to combine the image files into a single PDF rather than using iPhone's file app as the PDF producing software?