What are some alternatives?
When comparing Word Online and Apache OpenOffice Writer, you can also consider the following products
LibreOffice - Writer - Open-source cross-platform word processor.
Google Drive - Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Microsoft Word - Microsoft Word is a commercial word document processor for Windows.
Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
AbiWord - AbiWord is a free software word processor.
LyX - LyX is a document processor.