do I have to pay for a yearly subscription to microsoft office?

That's up to Microsoft but my guess would be no since Office 2011 is still functional if you don't upgrade to Catalina. The paid version is usually good for many years or until your system specs preclude it.

You can buy a standalone perpetual license for Office 2019 if you don't want to subscribe to Office365.

If you do that, you will not be automatically entitled to upgrades.

At this point in time, it's questionable as to whether Microsoft is actually going to release any more standalone versions or when they might do so.

Look into the Free LibreOffice, it handles MS Office files…

https://www.libreoffice.org/

Apple macOS (Mac OS X)

The software and hardware prerequisites for installing on a Apple macOS computer are as follows:

• LibreOffice 6.3.x: macOS 10.10 (Yosemite) or higher

• LibreOffice 6.2.x: macOS 10.9 (Mavericks) or higher

• Intel processor

• 512 MB RAM

• Up to 800 MB available hard disk space

• 1024x768 graphic device with 256 colors (higher resolution recommended)

It is a recommended best practice to back-up your system and data before you remove or install software.

Notes:

• For certain features of the software - but not most - Java is required. Java is notably required for Base.

• Due to an issue, there are the following restrictions with Java: on macOS 10.10 and newer, JRE isn't found, JDK is required

• LibreOffice 4.3 can still run on OS X 10.6+, but please understand that this support ended when 4.3 was retired on May 27, 2015.

https://www.libreoffice.org/get-help/system-requirements/#Apple

Feature Comparison of LibreOffice v6.3 with Office 365/Office 2019 for Mac

https://wiki.documentfoundation.org/Feature_Comparison:_LibreOffice_-_Microsoft_Office

starz83 wrote:

If I purchase that, am I going to have to purchase again in 2020?

Only if you want to get the upgrade to the 2020 version (or whatever the next version Microsoft releases is). Office 2019, is a standalone, single purchase version, and will conceivably continue to work normally without having to pay anymore past the original purchase price, for many years unless something changes again with macOS in the future like it it did with Catalina and it no longer works on it.

Its conceivable at some point in time it may suffer the same fate as Office 2011, and no longer work in newer versions of macOS in around 10 years time. But there is no way to know for sure when that will happen. Just know that at some point it will happen.

The software world is not eternal, at some point you need to upgrade every piece of software to work with newer hardware and operating systems, and Microsoft Office is no different. Don't expect to use the same piece of software forever.

LibreOffice is not a good choice where one seeks the same degree of document interchange fidelity that one would expect with strictly MS Office applications. It is a superset, and if one uses those features that are implemented differently, or not in MS Office at all, then there will be unpleasant surprises.

The Document Foundation has authored a LibreOffice/MS Office comparison guide, but I would still tread carefully where MS Office users are the ultimate recipients.

You can purchase Office 2019.

No but you can check Microsoft's licensing on the Microsoft site

Thanks. :)