The document discusses mail merge, a feature in Microsoft Word that allows users to personalize standard documents with recipient-specific information from a data source. It describes how to create a main document template and a data source spreadsheet, then merge the two to automatically generate individualized documents for each recipient. Examples provided include using mail merge for name labels, form letters, and other mass mailings. The document also discusses using mail merge for archiving letter systems in education offices to more efficiently generate correspondence.