Users can add an Attachment to nearly any Details page by using the Notes/Attachment feature at the bottom. This is true of Detail Pages for Jobs, Equipment, Chemical Application, Customers, Employees, Estimates, invoices, Catalog, Vendors, Properties.
Once you are in the Details page of a Job, Customer, Estimate, etc., simply scroll down to the Notes/Attachment box at the bottom of the page, and click on the ‘Add an Attachment Link’.