File Extension Basics

A file extension is a suffix added to a filename, typically separated by a period (.), to indicate the type of file and how it should be handled by the operating system or software.

Understanding the '.docx' Extension

The file extension '.docx' specifically identifies a document file created by Microsoft Word. It replaced the older '.doc' format starting with Word 2007.

Identifying the Correct Software

Based on the file extension:

• '.docx' is associated with word processing documents.
• Microsoft Word is the primary application used for creating and editing '.docx' files.
• Other options like MS Excel (spreadsheets, typically '.xlsx'), MS PowerPoint (presentations, typically '.pptx'), and JPEG (image files, typically '.jpg' or '.jpeg') use different extensions.

Conclusion

Therefore, the '.docx' file extension belongs to MS Word.