A file with DOTM extension represents template file created with Microsoft Word 2007 or higher. It is similar to the popular DOCX file format other than it retains the user defined settings for reuse in case of creating new documents. Such documents are more often used in offices where a standard template file is generated with settings like page information, margins, default layout and macros, and is used to create new documents from it when required. DOTM files, however, save macros, that are a series of commands in the form of recorded actions for automatic completion of a task. This helps save time in carrying out actions that are repeated in completion of a task.
Files with POTM extension are Microsoft PowerPoint template files with support for Macros. POTM files are created with PowerPoint 2007 or above and contains default settings that can be used to create further presentation files. These settings can include styles, backgrounds, colour palette, fonts and defaults along with macros that consist of custom functions for doing particular task. They may also be opened by a previous version of PowerPoint with Open XML document support installed. POTM files can be opened in Microsoft PowerPoint for editing like any other PowerPoint file.
You can also convert DOTM into many other file formats. Please see the complete list below.