Go to iTunes and download FileApp...it's free
Download your file
Select Open in
Choose Open in FileApp.
Tap the zip archive file.
Tap to open folder which will contain your unzipped files.
See extracted files listed.
Now select files to view and tap Done.
Here is the file, now tap on the screen then tap on the action tab.
See Actions tab.....Tap on 'Open In'.
See display of options to open your file in... Note the displayed option may depend on the apps you have access to.
I hope my instructions are clear. Please let me know if you have any questions. Thanks