To use Grammarly Desktop with the Craft Mac app, follow these steps:
1 - Download Grammarly desktop from their website: https://www.grammarly.com/desktop
2 - After installation, launch the Grammarly app and follow the guide to enable Grammarly in your Mac in Settings > Security Privacy > Accessibility:
3 - Restart the Craft app, and the Grammarly widget should be available whenever you select a block to be reviewed: