I find multiple questions/answers about automating Powerpoint 16 for OSX using AppleScript, such as: Using Applescript to open MS Powerpoint 2016 file
Where is the official documentation / API of AppleScript commands for Powerpoint?
Note: Yes, I googled it for a while before asking this.
Update
Powerpoint does not appear in Script Editor -> Window -> Library

I do not have or use Microsoft products and would assume if there was any official documentation, other then an applications AppleScript dictionary file, I'd suspect you have to acquire it from the developer of the application.
However, if any give application has more than basic support, e.g. open, close, quit, etc., then the application should contain an AppleScript dictionary file, i.e. appname.sdef that can be viewed from the Library in Script Editor.
Script Editor > Window > Library, or: ⇧⌘L
If it's not already in the Library , it can be added by clicking the (+) button and navigating to and selecting it in the dialog sheet that appears when clicking the button.
Once added to the Library, select the target application and either double-click it or click the icon of the books in the Toolbar of the Library.
No such documentation has been published recently. Microsoft did publish material like this while Office 2008 was on the market, because that version lacked VBA and AppleScript was the only way to automate it. Fortunately, I downloaded copies back then and have reposted them to my web site: Office AppleScript Reference - Cool Code
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