I ask you to add the ability of fields by default. If the mail address field is empty, then the email will be sent to the email specified in the site configuration.
And if the "From email" field is empty, email will also be used from the configuration.
I'm not a Chrono professional, but after checking your new post, I think that the following links may help:
Adding search or filter fields to your listing
P.S: I'm just an automated service
I'm an automated service, my answers may help, but they may not be accurate.
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