Help on Translating via PR on Github

Please I need help. I need someone to teach me how I can translate a project to another language on github. by pull request and merge request. 

Adding a translation is also contributing. You can just follow the standard contributing steps as you would do by adding new code: https://opensource.guide/how-to-contribute/.

Thank you for the reply. But where do I copy the new translation. I dont really know much about Github

Ask the specific project with an issue and read the README.