How to link to specific APIs

using this API (You will need to replace the value of apic-em with what works for you):

 https://apic-em/swagger#!/device-credential/getGlobalCredential

 The above  link was obtained by copying the URL from the browser while looking at the API. If I paste that link back in, though, all I see is the top level API page.  So, how can one actually link to an API in the documentation, so as to be able to explain which API one is using.

The APIs can be accessed at,

 https://<APIC-EM IP>/api/v1/<API>

The <API> may have some parameters that may be required or optional parameters.

 You may refer to the "APIC-EM API Reference" at,

 Cisco Application Policy Infrastructure Controller Enterprise Module - Programming Guides - Cisco

 For example, the device credentials GET API can be accessed at,

 https://<APIC-EM IP>/api/v1/global-credential?credentialSubType=CLI

 "credentialSubType" being a parameter.

 The question is about how to access the documentation for specific APIs. It is not about using the APIs. The first two links you have provided appear to be trying to explain how to use APIs, which is not the concern here.

This link:

APIC-EM API Reference

 From:

 Cisco Application Policy Infrastructure Controller Enterprise Module - Programming Guides - Cisco

 Leads to:

 https://anypoint.mulesoft.com/apiplatform/apx/#/portals

 After authentication, a list of APIs appears. A screenshot of that page is attached. As you can see from the screenshot, there is no explanation of what these APIs are. APIC-EM might be in that list somewhere, but I can't see it.

The right link should be in -  http://devnetapic.cisco.com/.

 http://devnetapic.cisco.com/#!/pnp-project/getPnpSiteByRange

 When I paste it into a browser, I end up at the top level swagger page, not down in the pnp-project API.