GitHub encourages collaboration practice in their community guidelines. The insights tab of your GitHub project provides a section called "Community" that includes a list of recommended documents that your project should have. Those include a README, Code of Conduct, Contributing guidelines, licence, and templates for issues and pull requests.
This chapter is an abbreviated version of the Mozilla Open Leadership Series material which is licensed under a Creative Commons Attribution 4.0 licence. The complete Open Leadership Handbook is available at https://mozilla.github.io/open-leadership-training-series/articles/readme/ and is highly recommended it as additional reading.