LibreOffice and OpenOffice are the two main competitors for Microsoft Office. Google Docs and similar software provide a lower level of functionality for simple documents but are not alternatives to the full Microsoft Office.
Microsoft used to offer Microsoft Works as a low cost alternative to Microsoft Office but most people ended up wanting a little bit more functionality. The upgrade from Works to Office was difficult. You could not receive an Office document from a customer then use it in Works. Works disappeared.
Google Docs has a similar level of functionality to Microsoft Works with the added problem that you have to be connected to the Internet to use Google Docs. The one advantage of Google Docs is the ability to have several people editing the one document at the same time. That can be useful for note taking at a meeting.
When you want something other than a simple document, you need LibreOffice, Microsoft Office, or OpenOffice. With those three, you can share documents with customers, suppliers, government departments, and anyone world wide.
Any operating system
Microsoft Office runs only on Windows. LibreOffice and OpenOffice run on every operating system for computing devices with enough grunt to handle a significant document. many operating systems now have LibreOffice installed by default or ready to install from their libraries.
For compatibility with Microsoft Office users, you can exchange documents in the Microsoft Office formats including .docx. When nobody needs Microsoft Office compatibility, you use the Open Document format files. Converting to and from the Microsoft file formats is easy if you need suddenly need Microsoft Office compatibility. Only a few very complicated word processing options fail to convert exactly the same.
You can also have font problems if you choose complicated fonts because they may be available only in one operating system. Most operating systems have similar fonts but some have weird names and do not fall back to a standard font. Some document creators deliberately select proprietary fonts for no useful reason. LibreOffice on the Linux Mint distribution of Linux is good at finding the right local font.
If you want to test compatibility of conversions between .docx files and .odt, choose a document with revisions and revision comments. From all the conversions I made, revision comments were the last thing to create problems.
LibreOffice or OpenOffice?
OpenOffice was the leading open source office software. Oracle became the owner of OpenOffice when Oracle purchased Sun. The open source developers then split off LibreOffice as the true open source descendent of OpenOffice. Oracle than passed ownership of OpenOffice to the Apache Foundation, a move that happened too late to save OpenOffice.
Today the choice is between the LibreOffice supplied with most operating systems or the Microsoft Office supplied in Windows. You only have that choice when you have Windows installed as your operating system or as one of the operating systems in a dual boot configuration. Which way do you go in the future?
Microsoft Project compatibility
I worked on a project where Microsoft Project was supplied by the organisation running the project. A Microsoft Windows 8.1 DVD cost me $138 delivered, ready for a dual boot of Windows with Linux. There was a free trial of Microsoft Office on the DVD but the free trial was not compatible with Microsoft Project. I had several Microsoft Office DVDs and none of them were compatible with Microsoft Project. The organisation then supplied a matching Microsoft Office but there was still a compatibility problem.
Microsoft Project shared code with Microsoft Office and had to have exactly the right matching version of Microsoft Office. This is a huge change for Microsoft, a real step down from the days when you chose Microsoft software to fix compatibility issues. Microsoft is now creating the problems.
LibreOffice worked in both Windows and Linux. LibreOffice did everything needed for the project and accepted charts, etc, created by Microsoft project. There is no longer a need to stuff around with Microsoft Office.
Dual boot? VM?
In a corporate environment, you may be stuck with something that runs only on Windows. Your request to use Linux may fail. If they reject Linux, ask about an alternative from Apple. After everyone converts to Apple, you can then dump the Apple hardware, buy the hardware you really want, and install Linux.
On your own hardware, you can run the remnants of Windows using dual boot or a virtual machine option. Running Windows in a VM under any other operating system is a real pain, some things work then you waste days on trivial problems you would not get with dual boot. Linux works under a VM inside of Windows but you lose some of the advantages of Linux. Dual boot is the easiest and works well when you only have to swap between operating systems once per day.
An approach to using Microsoft Office in the corporate world is to create all your documents in Linux using LibreOffice, save the final versions as .docx to a shared NTFS partition, then open the documents in Microsoft Office for a final check. After the final check, save the files from Microsoft Office then return to Linux to use Thunderbird, or equivalent email client, to send the documents to wherever they need to go.
There is also the option to run very old versions of Microsoft Office under Wine under Linux. Wine rarely works for the most recent versions of Microsoft applications. The compatibility of LibreOffice with Microsoft office is a few years ahead of the compatibility of Wine with Microsoft applications.
Microsoft office was costing me hundreds of dollars every three years to buy an update. The recent compatibility issues added thousands of dollars of my time to the real cost.
Microsoft Office requires Microsoft Windows, a cost of hundreds of dollars every few years. Plus Windows is as expensive to manage as Microsoft Office. Windows 7 was the last working version of Windows. Windows 8, 8.1, and 10 each cost thousands of dollars of my time. Windows 8.1 was the fallback after 10 failed to do anything useful. 8.1 is the closest to 7. Unfortunate I then needed to switch back to 10 for a project where Microsoft software again failed to work with Microsoft software.
After wasting about $15,000 of my time between Microsoft Windows and Microsoft Office, I can now delete Windows and the dual boot.
There was another cost created by Microsoft Windows. The install wastes so much space on bloatware that I had to buy a larger SSD for my notebook. If you are looking at using Windows instead of Linux, you have to buy the more expensive models of most notebooks to get the larger SSD to allow for the current and future bloatware.
There used to be reasons for using Microsoft Office and now they are gone. If you had Microsoft Office already installed, it was useful to leave Microsoft office on Windows as a dual boot option but now there are few reasons to keep Windows. I cannot find a reason to keep Microsoft Windows other than not having spare time to delete it.