Payments
Glad to have you back, @LunaJohn.
Allow me to join this thread and add some information about QuickBooks Online (QBO) Bill Approval Workflow.
Once the approver received the Bill Approval workflow email, he/she will see a link in the email that will route him/her to the Task menu.
If a workflow notifies one of your team members to review or approve work, QuickBooks creates a task. This is only the place where you can attach or upload a document. Here's a sample screenshot from my test file: 
In case you need it, I'm also adding these articles that will help you more about the Workflow feature in QBO:
I'll be around if you have any additional questions or concerns. Take care always!
