diff --git a/packages/core/README.md b/packages/core/README.md
index 8a471430..be942888 100644
--- a/packages/core/README.md
+++ b/packages/core/README.md
@@ -262,6 +262,15 @@ var pid = core.getState("pidToKill");
 
 process.kill(pid);
 ```
+#### Environment
+
+To check whether action runs on [GitHub Enterprise Server](https://docs.github.com/en/enterprise-server@3.10/admin/overview/about-github-enterprise-server) you can use isGhes helper:
+
+```js
+const core = require('@actions/core')
+
+const isGithubEnterpriseServer = core.isGhes()
+```
 
 #### OIDC Token
 
@@ -333,3 +342,5 @@ toPlatformPath('/foo/bar') // => \foo\bar
 // On a Linux runner.
 toPlatformPath('\\foo\\bar') // => /foo/bar
 ```
+
+