To access a form’s permissions, first navigate to the Forms app in Site Administration (your site’s menu) → Content & Data → Forms. Then click the form’s Actions button (), and select Permissions.
By default, you can grant these permissions for a form:
Delete: Delete the form.
Permissions: Access and configure the form’s permissions.
Update: Update form entries.
Add Form Instance Record: Submit form entries.
View: View the form.
Note that guest users can view and fill out forms by default. The Guest Role has View and Add Form Instance Record permissions.