Unwanted pdf rotation

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!