Embed external HTML in author guidelines

Hi there!
I’m looking for a way to embedd an external html file in sections like authoguidelines or about so I can edit its content on my computer and upload it right away with no need to go to edit and the copypaste the new content, is it possible?
Im using ojs 3.1.2 at this time with default responsive theme
I tried to use an iframe but the result is not responsive and has those ugly side scrollbar .

Thanks in advance!

One of the magazines: