Relate document with opportunity using formula

[Enju]

Hello,
Is possible to relate document with opportunity using formula?
I would like the attachments that were attached in the attachments field in Opportunity to be linked as Documents.
Thank you!

[emillod]

Hello Enju
do you want to write a formula which will start attaching files for new opportunities? Or you want move already existing attachment to documents section?
Do you have advanced pack?

[Enju]

Hello emillod
I wont move already existing attachment to documents section.

This will be a more complex formula but I got stuck trying to attach attachments to the Documents section:
If I send an email that is related to Opportunity and contains attachments with a specific name, e.g. Invoice.pdf, I want to attach these files to the Opportunity-related documents section.

[emillod]

You should read about duplicating attachment based on sourceId.