Hello dears
I hope you are well ...
Today I have problems with some if at the time of adding a new page.
I have a system in which a person must charge if a process is paid or partially paid.
When adding the page I want it to multiply the value of the amount field by 1.21 if you choose cash in the form of payment field. But if it is with a credit card, leave it like this or multiply it by 1.
Likewise, if the payment is made in full, change the payment status field from non-payment to payment.
as they recommend that you perform this procedure.
I await your comments. Thank you so much