Actions are steps upon a contact's path within an Automation.
Click the [+] sign to add an Automation Step.
On your Automation Step, click Actions, select the Action you'd like to add, follow the specific instructions, then click Save.
You can take the following Actions within your Automations:
Change field value
Update pipeline status
Send text message
Request info through text message
Notify team member via email
Notify team member via text message