You will need Full Write Workflows permission to perform this task.
If you haven't already done so, build your form first: How do I design a form? If you plan to send respondents into a workflow, set up the workflow ahead of time: How do I add processes to a workflow?
Add an automation that runs on every submission
From the left navigation, click Forms and open the form you want to add automation to. On the form, click the Settings tab, then the Automations sub-tab.
Click + Add Automation. In the Add Form Automation dialog, choose a Type:
Group: pick a group in the Group search field. Anyone who submits the form is added to that group's Members automatically.
Workflow: pick a workflow (and the task within it) in the Workflow dropdown. Anyone who submits the form is entered into that workflow at the chosen task.
Click Add to save the automation.
Note: after you add a Group automation, any submission that can't be matched to an existing person profile will create a new person profile.
Tip: a Group automation adds people straight to the group's Members roster, with no approval step. This is true even when the form is also an event's registration form, so you won't need to approve these people from the group's Sign Ups tab.
Add an automation that runs only for a specific response
Automations can also be tied to a specific answer on a single field. Yes/No, Dropdown, Radio Button List, and Checkbox List fields all support per-response automations.
For example, the form below has a list of options as radio buttons:
Open the field's editor (click its 3-dots menu on the Fields tab and choose Edit) and switch to the Automation tab. Click Add Automation to set what should happen when a respondent picks a particular option. You can configure different actions for different responses on the same field.
Note: automations on the form's Automations sub-tab run on every submission. Per-response automations run only when a respondent selects a specific answer. Use whichever fits the workflow you want.
Route email notifications with routing rules
Routing rules decide who receives the Admin Email when someone submits your form. You can notify the same people on every submission, or send each submission to different people based on how the respondent answered. For example, you could send each campus's submissions to that campus's staff, or send each choice in a "Which volunteer team are you interested in?" field to a different team leader.
On the form, go to Settings > Notifications.
In the Routing Rules section, click + Add New.
In the Add Routing Rule dialog, choose an Action (see the options below).
If you chose a response-based action, check the answers that should trigger this rule. Click check all to select every answer.
Under Recipients, use the search mode menu to choose Person, Group, or External, then add the people who should be notified.
Click Done.
Action options
General
On Form Submission: notifies the recipients on every submission.
On Field Response: notifies the recipients when the respondent picks specific answers on a Yes/No, Dropdown, Radio Button List, or Checkbox List field you added to the form.
Submitter
On Campus Response: notifies the recipients based on the campus the submitter chose.
On Gender Response: notifies the recipients based on the submitter's gender.
On Marital Status Response: notifies the recipients based on the submitter's marital status.
Each Submitter action lists that field's values, plus (Blanks) for submissions where the respondent left it empty.
The Submitter actions only appear when the form collects Campus, Gender, or Marital Status in its submitter (Person Info) section.
Tip: create a rule with On Form Submission to act as a default, so someone is notified about submissions that don't match any of your response-based rules.