Both are Microsoft Word document files. ".docx" is the new file extension that newer Microsoft Word version uses while the older versions save word files as ".doc" files.
Doc can be read in all MS Word versions but Docx can be only read in Word 2007 and later version unless you have installed some adds-on or compatibility packs in MS Word 2003;Docx file size is 75% less than the file size of doc;Docx files can easily convert into doc, .html, .rtf and other file formats, but a doc has to be converted in the aid of professional software;Docx is an opener file format that can be easily accessible;Docx is more powerful and versatile on features.
.ppt is Microsoft 2003 or earlier word file while .pptx is 2007 and up.
.doc or .docx
The standard extension for most versions of Word has been .doc but in Word 2007 .docx is used.
Yes MS Word is a doc file. The file extension of MS Word file is .doc, .docx, .docm and many more.
.docx
The same reason .doc became .docx.
*.doc and *.docx files open Microsoft Word
doc for Word 2003 and docx for Word 2007
*.doc or *.docx
.txt .doc .docx (Most common)
.docx is the default file format for documents from Word 2007 onward.