Why can't I open AOL attachments on my iPhone 6S Plus

[iMore Question]

At the bottom of the email I am viewing on my AOL mail on my iPhone, the attachment has brackets around it and I cannot open, either Word documents or PDF files. I think there is a setting in my iPhone to be able to view the attachments, but I cant find it! Thanks!

 

[Just_Me_D]

What email app are you using? Do you have an app installed that supports the format that the attachments are in?