Vote +1 for Open Office or Libre office. They are open source AND the file format OpenDocument (odf) is an open standard (ISO 26300) AND both will do all of your requirements. Here is a recent review with a quick compare of Libre vs OO: What LibreOffice and Apache OpenOffice Have Taught Me and there are other reviews, just search Google. Best is just pick say LibreOffice (make sure its the official Libre site) and install and play with it. The interface will be different to MS Word but not more so than the next version of MS Word is to the present one
(The entire story of word processing document file formats is decades long and very nasty from one particular company.)