Using GitHub Checks
By default, CodeFactor updates Pull Request's status during review. E.g.:
To view any reported issues you must click Details link and visit CodeFactor page with review results.
A more integrated approach would be to report issues as code comments inside pull request and this is what GitHub Checks feature is for. To enable it go to repository Settings page and click Enable under GitHub App panel:
If you'd like to revert back to status-only reviews, click Update under GitHub App panel or visit App install page on GitHub to perform uninstall.