Microsoft Office 365 is an amazing software that helps companies establish their business, so a backup is a must since Microsoft is not offering the proper backup.
LibreOffice - Free office suite, open source, and compatible with .doc, .docx, .xls, .xlsx, .ppt, .pptx files. Updated regularly – download for free. Originally based on OpenOffice.org.
G Suite - Google's encompassing suite of cloud-based business apps.
WPS Office - Would you need Office Word, Excel or PowerPoint for Home, business or School? WPS.com would give you right version for you.
ONLYOFFICE - ONLYOFFICE is a complete office and productivity suite.
Google Drive - Access and sync your files anywhere
Apache OpenOffice - Apache OpenOffice is an open source, office document productivity suite.