When you qualify a lead in Rental Management for D365 Sales:
An account is created in Rental Management for D365 Sales.
In Rental Management for D365 Sales, an account is a company with which you (potentially) do business.A prospect is created in D365 F&SCM.
In D365 F&SCM, a prospect is a company with which you potentially do business.
The account in Rental Management for D365 Sales and the prospect in D365 F&SCM are linked.
Note
If, for the lead, you have entered an account name that already exists as an account, a dialog is shown where you can indicate what to do with the duplicate account.
If, on the Qualify dialog, you have selected an existing account, no account is created. The created opportunity is linked to the existing account.
If you have selected an existing account, usually, already a related prospect or customer exists in D365 F&SCM. In this case, no prospect or customer is created in D365 F&SCM.