These options are only available for standalone forms, not child forms (i.e. forms used in a portal or shared view or for linked record fields in a main form).
By default, the form just shows a standard success message. However, you have other options:
1. Show a success message.
This custom message could either be static or coming from an Airtable field. Set a Success Message Delay when you are using an Airtable field as a source of the success message to ensure that creation or update is already finished prior to displaying the message.
2. Redirect to URL.
This redirect URL could either be fixed or a value of an Airtable field.
3. Close the form
A success message will be shown to confirm the successful submission and then the form will automatically close after some time. Set a delay to provide enough time for your users to read the success message.