How can I attach a document to my booking?

I'd like to include the supporting documents of an itinerary in a the itinerary PDF. So that the client has all vouchers in a single document.

You can embed the uploaded document links in the notes section of a booking.
 
First, upload the PDF to the documents section of the itinerary.
Second, click on the document to open it.
Third, copy the long link in the browser.
Fourth, paste it in the notes section of your booking.
 
You can make the link clickable or turn text into a hyperlink.
 
Info on hyperlinks:
https://support.axustravelapp.com/hc/en-us/articles/360033276592-Create-a-Hyperlink-in-the-Text-of-Your-Itinerary