You can add photos, pdfs, and documents to specific contacts, companies, deals, and cases. Any user that has permission to that particialr piece of data will have access to the file.
In order to use files, the account must be on the Pro plan or higher.
Go into the contact, company, deal, or case, and below the information box on the right side of the see, you'll have a Files section.
Click the Add Files button, find the file on your computer and click add. Once added the file will remain within the contact, company, deal, or case.
If you need to access the file at a later date, click on the file name. Depending on the type of file, it will either open in karma (photos and pdfs), or it will download the file to your computer. This is not meant to edit the file while in karma. If you edit a document, you will need to upload the new file.