How to move multiple documents from one Appian environment to another Appian environment

You can export documents as part of an application or patch, just as you would for any other design object! In your case, it sounds like the documents are already part of an application, so when you export that application, the documents will be included in the export package.

You can actually select the documents in batches of 25. So, even with a few hundred documents, I wouldn't expect it to take more than a minute or two to add them to a patch.

You could also simply export the application.

While the two options above would probably be my go-to approach, Appian also allows you to download a document folder or knowledge center (and all its contents) as a zip. You can then upload that zip in a single step and everything will be unpacked for you. docs.appian.com/.../Document_Management.html (Note that the maximum number of documents that can be exported as part of a single zip is 5000, and the maximum upload size is 1GB by default).