First, create a new module (Project > Module) and give it a unique name.
Next, create a Send Email task (Email & SMS > Send Email) within this module.
Finally, under the specified task to check for errors, select the "call:[module]" option within the "On Error" panel, where [module] will be changed to the name of the module containing the Send Email task.
If you want a simple test to see if it works, you can use a "Raise Error" task (Job Control > Raise Error) and still use the On Error panel to route to the module where you can send an email.
After executing, you can see in the Job Log that there is a [9001 - Raise Error] log that will route the control to the other module, which will then send the email.