Enhance README for improved contribution usability (dotnet#9451)

Author: JoanGil

README.md

@@ -1,7 +1,18 @@
 # .NET API Reference Docs
 
-This repo contains documentation for the .NET API reference. We track all work for this repository using [GitHub issues](https://github.com/dotnet/dotnet-api-docs/issues). The documentation for APIs is built from the text and code snippets in this repo, and from the samples in the [dotnet/samples](https://github.com/dotnet/samples) repository.
+This repository contains documentation for the .NET API reference. We track all work for this repository using [GitHub issues](https://github.com/dotnet/dotnet-api-docs/issues). The documentation for APIs is built from the text and code snippets in this repo, and from the samples in the [dotnet/samples](https://github.com/dotnet/samples) repository.
 
 The repository for conceptual .NET documentation is the [dotnet/docs repository](https://github.com/dotnet/docs).
 
+## :purple_heart: Contribute
+
+We welcome contributions to help us improve and complete the .NET API reference docs.
+
+To contribute, see:
+
+- The [.NET Contributor Guide :ledger:](https://learn.microsoft.com/contribute/dotnet/dotnet-contribute) for instructions on procedures we use.
+- Issues labeled [`help wanted` :label:](https://github.com/dotnet/dotnet-api-docs/issues?q=is%3Aopen+is%3Aissue+label%3A%22help+wanted%22+) for ideas.
+
+## :bookmark_tabs: Code of conduct
+
 This project has adopted the code of conduct defined by the Contributor Covenant to clarify expected behavior in our community. For more information, see the [.NET Foundation Code of Conduct](https://dotnetfoundation.org/code-of-conduct).