Hi there,
Now a days listening to documents is more preferred than reading it out, it saves time, you can even multitask and above all can retain the information for a longer time.
The following are some of the apps that would read aloud your pdf:
Adobe Acrobat
eReader prestigio
Xodo pdf reader
Natural reader text to speech
Voice aloud reader.
Pdf speaker.
Hope this helps.
Best wishes.