With the Ottspott Phone Widget, you can easily create new contacts. When you receive a Slack notification from the Ottspott phone widget, you have in the bottom of notification an "Add contact " button .
When you click on this button, a form appears to create a new contact. You can choose where this contact will be created.
Either in the Ottspott database or in your CRM/Helpdesk tools if you have an integration enabled with Ottspott.
Form in Slack: