Resources:
[docs](https://docs.github.com/en/apps/creating-github-apps/authenticating-with-a-github-app/generating-a-user-access-token-for-a-github-app#using-the-web-application-flow-to-generate-a-user-access-token)  and [tutorial](https://docs.github.com/en/apps/creating-github-apps/writing-code-for-a-github-app/building-a-login-with-github-button-with-a-github-app).

Use [@octokit/core.js](https://github.com/octokit/core.js) or [@octokit/request.js](https://github.com/octokit/request.js/) framework [modules](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules) for interacting with the GitHub API. Don't write your own code for this.