I created Azure load balancer using a scale set. so I have 2 instances of Windows server 2016 running. My web portal is up and running whenever I try to save data it only gets saved on 1 instance rather than both how can I keep them in SYNC?
There is no built-in data sync feature in Azure Scale Set. However, you could create a scale set by using a custom VM image including all required application installed to reduce the post deployment task.
When you create a scale set, you specify an image to be used when the VM instances are deployed. To reduce the number of tasks after VM instances are deployed, you can use a custom VM image. This custom VM image includes any required application installs or configurations. Any VM instances created in the scale set use the custom VM image and are ready to serve your application traffic.
For more references:
Tutorial: Create and use a custom image for virtual machine scale sets with the Azure CLI