The documents tab is found on account, Kb article, lead, opportunity, Product, Quote and Sales Literature. It will only be available if SharePoint integration has been setup.
It can be seen on the fifth tab along when viewing an account
Where should you also check that documents have been enabled for each entity?
You need to go to customisation and enable it for each entity you want to use it for. You can also do this for custom entities.
What’s inside the documents tab?
When you select the documents tab CRM will check for any Document locations/folders for this particular record name which exist in SharePoint. From here you can create new documents, new folders, open a folder location within SharePoint. The large drop down is the document locations and there are two areas you can create a new document location and one area you can create a new document or document folder.
Documents tab missing
Please ensure you are using and have setup the Sharepoint integration.This has occurred sometimes and is a known bug. Recycle the app pool and then clear the temp internet files and restart the browser.