When selecting information from your trigger app, you will most likely be offered a list of possible options to choose from and how to select the correct file is not always clear. 

In this example using the Gmail app as trigger in our Zap, we are trying to print an email attachment with ezeep Blue. The object reference "Atttachment(exists but not shown)" is the file reference we are looking for.

It is common for apps to show "File(exists but not shown )" or "Attachment(exists but not shown)".

Here are a few examples that show what object reference you should pick in Zapier to print a file with ezeep Blue:

App Name Use Case  File Description 
Gmail printing an attachment from an email Attachment (exists but not shown)
Google Drive
Printing a new file added to a folderFile (exists but not shown)
OnedrivePrinting a new file added to a folder File (exists but not shown)
Signority Printing a new completed contractFile (exists but not shown) 
Zoho WriterPrinting a new file added to a folderFile (exists but not shown)
DocusignPrinting a completed contractFile download link (exists but not shown)
Printing a completed contract File contents: (exists but not shown)
printing a newly uploaded file File (exists but not shown)

As you can see there are some variations in the way each app describes the file reference, however, each file reference is followed by "(exists but not shown)"