Configure Faxes for Health Cloud
You can user Opero Fax, Salesforce app with Salesforce Health Cloud and get your received faxes into Health Cloud’s “Received Document” object.
Check that under Fax Configuration you are set for getting Received Faxes as Files instead of Attachments (Salesforce Classic). By default the fax app will use Files, but if you are are an older customer you may still be configured using Attachments. Check basic configuration article for more info.
When you install Opero Fax, a custom object called Received Fax is created. Every time you receive a new fax a new Received Fax record is inserted in your org with a related File of the PDF of the fax.
The field Received Fax.efaxapp__Fax_URL__c contains the content/file id of the related PDF file. Check an existing record to see what the value of this field looks like to identify what you need to trim in order to just get the file id/content id. You can create a formula to get the file id from this field. Or you can also query for the related File on Received Fax to get the file id.
Now you will create a Flow or apex trigger based on a new Received Fax record being created. The Flow should get the file/content id of the related PDF of the fax then create a Received Document record (object from Health Cloud).
In the Flow the next step would be to create a Content Document Link record to join these two IDs, with the sharing mode to I (inferred).
Sample Flow Configuration Guide
Record Trigger Flow based on Received Fax object
Flow Conditions
New Resource: Formula for contentDocumentId
Create Record: Create Received Document
Create Record: Create Content Document Link
Check this article on Salesforce for some further details on the Received Document integration.