A PUB file is a document created by Microsoft Publisher, a desktop publishing program used to create professional documents and marketing materials. It contains text, raster and vector images, and drawn objects formatted in a document.

PUB file open in Microsoft Publisher 2016 Publisher is used by casual and professional users to design page layouts such as newsletters, brochures, and posters. The program only comes with Office 365 editions of Microsoft Office, whereas the basic editions only include Word, Excel, PowerPoint, and OneNote. When you save a document in Publisher the program creates a PUB file to store the contents of the document. The file enables you to save edits to your document and allows you to close the file and open it again for further editing. PUB files are not only used for page layouts, they may also be used to integrate and store data sources for mail merges and generating data sheets. If you have a large amount of text in your PUB document that you want to reuse for other purposes you can export it to a .DOCX file for editing in Microsoft Word. The text and font formatting will be saved but any graphics or columns in you document will not be preserved. To save your PUB file as a DOCX file select File → Save As, choose the Word document format you want to save the document as, then click Save. PUB files can also be opened by several other applications. Some notable ones are LibreOffice Draw, which is packaged in LibreOffice and CorelDRAW, which is part of the CorelDRAW Graphics Suite. PUB files can also be opened in Adobe InDesign, one of the most popular desktop publishing programs, with the PUB2ID plugin installed.