Only two styles showing as you are apparently seeing...
If only two referencing styles are showing changing your Word language settings to English US may get the others there. Note they are likely still not a current edition. See how to i get harvard referencing?
What follows is my general advice on people asking about the Reference styles available in Word. Let’s start with Word Wizard’s analysis of the situation in January 2026.
From WordWizard:
Microsoft may never update the XSL files that create the citations and references in Word for the different style guides for a variety of reasons:
- They have not updated any of the XSL files for almost two decades, despite many request from users to do so. If they intended to keep these files updated, they had plenty of time and opportunity to do so.
- From a business perspective, one can understand why they might have chosen not to update the XSL files. Microsoft has no control over what a style guide contains, and these guides change periodically. So updating/creating XSL files to match style guides becomes a constantly moving target. Also, many institutions and universities use their own style guides or make modifications to existing ones. So there are many more style guides beyond the 12 files that Microsoft provides with a Word installation. Including support for these guides in response to user requests would increase the number of files that Microsoft would need to create and maintain which is not very likely to ever happen.
- When Microsoft released the XSL files, they provided several web pages that describe how to create or modify the files. So, one might surmise that Microsoft decided to leave it to the user community to update the XSL files themselves. BibWord on github was one example that did this. Unfortunately, none of the XSL files Microsoft provides are commented, and the guidance Microsoft provided on its web pages is inadequate, except for making simple changes. One has a very steep learning curve to overcome before creating new files to support new style guides. Updating the XSL file for APA from v6 to v7 wasn't very difficult since there were only few changes between the two versions. What changes are needed to update the Chicago XSL file from v16 to v18 is an unknown.
- Finally, Microsoft has more recently begun adding links in Word to 3rd-party plug-ins that provide support for citations and bibliographies. These links were added to both Office 365 and to some non-365 versions of Word. So, one could conclude that these links are Microsoft's answer to how it intends to provide support for citations and bibliographies for the various style guides. Unfortunately, many of these plug-ins don't operate seamlessly in Word, and do not provide the same functions as the XSL files. Additionally, most do not support all the different types of sources that are found in a style guide. So, until someone updates the Chicago XSL file to v18, the only solution you currently have is to use a 3rd party plug-in.
WordWizard does not know why Microsoft does what it does. No one here really does. We are your fellow users.
You could write a new bibliography file. This is not simple. If you do it, please consider sharing it. https://learn.microsoft.com/en-us/office/vba/word/concepts/objects-properties-methods/create-custom-bibliography-styles?source=recommendations
This has been done for APA 7th and is available for free download. https://github.com/briankavanaugh/APA-7th-Edition I and many other users have used this in the years since it was first put out there.
If I were attempting to do this myself, I would start by getting a good analysis of the changes from the version currently in Word and the version you would like. Then make a copy of the xls file for the old version and try to modify that. If you do this, I urge you to post something here with a link to what you’ve done so that others will not have to reproduce your work. (I have not done one of these myself.)
APA 7th
A good Word bibliography file has been produced by fellow users. See https://learn.microsoft.com/en-us/answers/questions/5124582/apa-7th-edition-in-ms-word-(2)?forum=msoffice-all&referrer=answers.