How to automatically approve an entry when submitting the form
By default, when submitting the form, the initial approval status is set to "unapproved", which means this entry hasn't been approved or disapproved yet. The unapproved status is represented by this yellow circle in the image below:
In case you want to change this behavior to have an entry automatically approved after submitting the form, then you must add GravityView's "Approve/Reject" special field to your form.
After adding the field to your form, you must click on the green checkmark under the Choices section so the field value is automatically checked by default. This field is only visible to administrators.
That's it! Now every form submitted will be automatically approved.