Hello,

1. Give portal access to your customer so they can login into their system.

2. I guess you want to allow them to upload direct documents instead of uploading a document via interface Sales, Invoice, Project, Task etc. If not like that then copy the menu Settings >> Technical >> Database Structure >> Attachments under Messaging menu. So your portal customers can able see that menu. Please define proper data access rules and access rights so customer can't see your inhouse documents.

3. Here in this menu your customers can upload their documents and later you can able to download them.

4. However your customers can already able to upload their documents via Sales, Invoice, Project, Tasks & Issues screen. At any screen there will be area called "Attachments". From there your customer can upload their documents related to particular record. Later, you can see and download those documents from Settings >> Technical >> Database Structure >> Attachments menu. (For this, you have to install Document module )

Let me know still you are confused.

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