Files with DWG extension represent proprietary binary files used for containing 2D and 3D design data. Like DXF, which are ASCII files, DWG represents the binary file format for CAD (Computer Aided Design) drawings. It contains a vector image and metadata for the representation of the contents of CAD files.
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.
You can also convert DWG into many other file formats. Please see the complete list below.