N Docs allow you view documents on Android. No internet connection is required.

* Support file types

- Microsoft Word(DOC/DOCX, don't support password protected file)
- Microsoft Excel(XLS/XLSX, don't support password protected file)
- Microsoft PowerPoint(PPT/PPTX, don't support password protected file)

- Open/Libre Writer(ODT, Open with thirdparty app)
- Open/Libre Calc(ODS, Open with thirdparty app)
- Open/Libre Impress(ODP, Open with thirdparty app)

- Hancom Hanword(Open with thirdparty app)
- Hancom Hancell(Open with thirdparty app)
- Hancom Hanshow(Open with thirdparty app)

- Portable Document Format(PDF, support password protected file)
- RTF
- TXT
- CSV
- MARKUP(MD/HTML/XHTML/XML/DTD/XSL/XSLT...)
- CODE(JAVA/CPP/PHP...)
- EBOOK(EPUB)
...

* Create file types :
- PDF
- TXT
- HTML
...

* Edit file types :
- TXT
- MARKUP(MD/HTML/XHTML/XML/DTD/XSL/XSLT...)
- CODE(JAVA/CPP/PHP...)
...

* Document Search
- Support all of file types, except PDF.
- PDF will be supported.

* Storage services

- Google Drive
- Microsoft One Drive
- Box