Can I Save Word Document as .docx with Kingsoft Office?

Yes. The latest Kingsoft Office Suites (both Office Free and Office Professional) support saving documents as the Microsoft Word 2007/2010 Open XML formats, these are: .docx, dotx, docm, dotm.

save document as docx with kingsoft writer 2013

To convert .doc document to .docx, you need to open it in Kingsoft Writer 2013, and press Writer > Save as > Microsoft Word 2007/2010 Document (see following picture). In the pop-up Save as window, the *.docx type is chosen as default (see above picture). Press Save.

save document as docx