Another free option, in addition to LibreOffice, that hasn't made it to my Web site yet, is:
FreeOffice (free)
https://www.freeoffice.com/en/
You might like FreeOffice even better that LibreOffice. For instance, I tested FreeOffice's compatibility with complex Microsoft Office files, and I found it to be superior to LibreOffice in this regard.
Downloaded this last night and played with it a bit this afternoon. Must say I'm impressed with the free suite as it surprisingly offers many things as their paid for full version. Most of what's left off from the free version are things that most users would not normally need anyway. One option that you will like is the ability to open, edit, and save files as *.docx. The free suite will save to *.docx by default once that option is chosen. As for font availability, I had no difficulty viewing all my Apple fonts. Why they were not available in the trial version of the paid for suite, I do not know. Might have been user error. LOL.
I only tested the word processor so I can not comment on their spreadsheet or presentation versions. However, the free Keynote and Numbers from Apple are hard to beat.
The free suite will also save documents to PDF, RTF, and TXT if so desired. And if you don't want or need the spreadsheet or presentation apps that come with the suite, they can easily be removed without disturbing the overall software. Something you can not do with LibreOffice.
One thing to keep in mind about other Office suites vs MS Office: If you have favorite templates that you use or templates that you designed for MS Office, they will have to be redesigned for the Free Suite or for that matter, LibreOffice or any other suite.
Overall, I recommend the Free Suite as an alternative to MS Office.
Our thanks to Randy for finding it.