You may use the Azure Service Bus REST API. To read a message, you may use
- Peek-Lock Message -> https://learn.microsoft.com/en-us/rest/api/servicebus/peek-lock-message-non-destructive-read
- Unlock Message -> https://learn.microsoft.com/en-us/rest/api/servicebus/unlock-message
To understand how postman shall be used, please refer the following