This question is very simple, you can refer to the following post.
1. Deploy create-react-app with azure pipelines
2. Unable to deploy React JS application on Azure App service
3. Process for React App deployment to Azure Web?
Suggestion:
It is recommended to choose linux when creating a webapp.
Configuration->StartupCommand:pm2 serve /home/site/wwwroot --no-daemon --spa
CLICK HERE to find out more related problems solutions.