Woocommerce checkout functions

First function:
I have on the the checkout page a custom field - checkbox with id: billing_wooccm14
Would like to add a function if this checkbox is checked and order is completed by customer then send the admin Complete Order Email to xxx@xxx.com email also. If not checked then do not send email to xxx@xxx.com email (only for admin as usually).

Second function:
I have a custom field named Billing email. ID: billing_wooccm13
If this field is filled with email then send customer emails also to this email. Like a second email. If not added then send the client order conformation emails as usually.
For emails I mean the default Woocommerce emails that are sent to Customer: Order on -hold, Processing order, Completed order, Refunded order, Customer invoice/Order details.

Similar function is available there (but not exactly what needed) shorturl.at/vINQ8

This two functions are needed asap.