Hi,

You can add the below code to change the email to in the invoice. 

For that create a custom model by inhering the model mail.mail, and add below function in it.

@api.model_create_multi

    def create(self, values_list):

        new_mails = super(MailMail, self).create(values_list)

        if new_mails.model == "account.move":

            for recipient_id in new_mails.recipient_ids:

                if recipient_id:

                    if recipient_id.invoice_email:

                        new_mails.email_to = f' "{recipient_id.name}" '

                        new_mails.recipient_ids = [

                            (5, 0, 0)]

        return new_mails

The above code is only applicable for invoices, if you need to achieve this for all you can remove the condition of checking the model "account.move".

Note: replace the field "invoice_email" with your new mail field 

Hope it helps

I've tried this, and even though my information shows up exactly like in your screenshot, the invoice is still sent to the customer. I turned off the auto-delete in the invoice template so that I could see what was happening on the back-end, and the customer's information still populates in the "To (Partners)" field.