TXT is a file format that contains the text, organized in rows. Text files opposed binaries that contain data that is not intended for interpretation as a text (encoded sound or image). The text file can contain both formatted and unformatted text. Since the very simple text files, they are frequently used for storing data.
A file with the DOCM file extension is a Word Open XML Macro-Enabled Document file used in Microsoft Word. It was introduced in Microsoft Office 2007. DOCM files are just like DOCX files except that they can execute macros, which lets you automate repetitive tasks in Word.