Documents can be uploaded in various locations e.g. General Docs tab, Shared Docs etc. or on the record's Documents tab.
Click on browse to select the document you would like to upload. If you do not enter a title, the file name will display by default.
The document type needs to be consider carefully since it can impact users access. Please read the article called 'Document Types - Controlling what documents user can see' for more details.
Expiry date will assist you in ensuring that all your documents are current e.g. qualifications.
Last but not least, there is an option to add a link instead of a document.