There is not built-in way to know if a User was created, but what you can do is write a custom service to create Users which triggers an event. You can use the CreateUser snippet found in the service editor, and then trigger the event by first creating an event on the Thing, then going to the "Me" tab in the service editor and selecting the blue arrow next to the event you just created. You also will need to import the MailServer extension which can be found on the ThingWorx Marketplace. Here, you will need to create a new thing with the MailServer template, configure this to use some existing mail server to send and receive emails, and then create a subscription to your event on your thing which sends an email using your MailServer. An example of how to configure the MailServer for Gmail, as well as some known issues that may need to be resolved with your IT department in order to use this extension, can be found in KCS Article CS236135
Hope this helps!
I tried the steps you mentioned but subscription part is not working. I follow below stepls. Please correct me if i am wrong
1. Creating Thing (Testing)
2. Creating Service "CreateUserforTesting" through CreateUser service snippet in "Testing" thing.
3. Creating Event "TestingUserEvent" in "Testing" thing
4. No idea about how to trigger this "TestingUserEvent" on creation of User. Because Create user snippet does not allow any extra code in snnippet.
4.Subscribe this event for sending Email.
You trigger the event in the service you created in step 2. In the service editor, go to the "Me" tab and select "Events" from the list on the left-hand side. Hit the little arrow button for the event you added, set any of the parameters as needed, and call this last in your service. Then, subscribe to this event and in the subscription, call a service that sends emails.