For a better understanding of Azure VNet service endpoints, you might need to consider the following key points:

• This feature cannot be enabled for virtual networks deployed with the ASM model, but it is supported for virtual networks deployed with the ARM model.
• This service endpoint cannot work with traffic from your on-premises environment.
• Using virtual network service endpoints will incur no charges.
• Make sure that there are no running tasks when you want to enable/disable service endpoints to a specific service (Azure Storage and Azure SQL Database) for a subnet.
• You cannot create multiple service endpoints for one service (Azure Storage and Azure SQL Database) on the same subnet. However, you can create multiple service endpoints for multiple services on the same subnet.
•  You need to make sure that all Azure services for which you want to enable service endpoints for, exist with the virtual network on which the service endpoints are enabled in the same region.
• If you have storage accounts with Geo-redundant storage (GRS) or Read-access geo-redundant storage (RA-GRS) enabled, you do not have to worry because service endpoints can span across the region on which they are deployed and the paired region. However, ensure that the primary storage account exists on the region on which the virtual network is located.
• The virtual network with service endpoints enabled can be in another subscription, and it would still work with the service for which you want to enable service endpoints.