How to attach document url in sms as e-bill

I am using EBS 12.2.10 with database 19c (19.18.0.0.0)

Requirement is to send e-bill to our customers through an sms. We are already sending sms to our customers on several event like order booking, order collection etc.

Normally we receive e-bill in the sms following with url on which customer clicks and document is downloaded / opened.

But I am asking from developer point of view what are the steps need to be considered for this modification. Where to store files (cloud or on-premise system), how to generate url and when user clicks on it, how it get processed and shows document?

I need general guidance / recommendations to achieve this functionality.