Azure App Service is a service used to create and deploy scalable, mission-critical web apps.
Once you delete a web app, you have the option to restore it in next 30 days. Refer: https://techcommunity.microsoft.com/t5/apps-on-azure-blog/restore-undelete-deleted-web-apps/ba-p/2922088
https://learn.microsoft.com/en-us/azure/app-service/app-service-undelete
Azure app service support custom backups, where it will be stored in a storage account and can be used to export your app service and restore it later. Refer:
https://learn.microsoft.com/en-us/azure/app-service/manage-backup?tabs=portal
Hope this helps