Mark the fields read only in your field settings like normal, and then conditionally disable it with this function. Include readonly='administrator' in your [ formidable] shortcode, and use this example to process it.

Use the code below to set a custom value in a repeating field. Replace 508 with the ID of the repeating section field. Replace 11700 with the ID of the field that you want to modify.

There may be times when an email or another form action is set to trigger on update or after successful payment, but you really only want it to trigger once. This example uses two hooks: one to set when an action has been triggered, and one to stop it the next time.