Hi EKL,
The best way is to set up SharePoint Online with customer engagement apps (Dynamics 365 Sales, Dynamics 365 Customer Service, Dynamics 365 Field Service, Dynamics 365 Marketing, and Dynamics 365 Project Service Automation), this will allow you to:
- Create, upload, view, and delete documents stored in SharePoint from within customer engagement apps.
- Use the SharePoint document management abilities within customer engagement apps, such as checking the document in and out and changing document properties.
- Enable non-customer engagement apps users, such as customers who want to review a bid, to directly access the SharePoint documents, provided they have the appropriate permissions.
You can read more about this here.