Hello, Greetings! of the day. As mentioned in project description, your requirement is to implement additional information form, with following fields on checkout page on your wordpress website.
1) Buyer's Special Instructions, this field should be textarea field.
2) Buyer's Preferences, this field should be drop-down field or multiple choice field.
3) Buyer's Secondary Contact Details: This part of form should collect another method of communication from buyer, such as secondary phone number or email address.
To implement this functionality, the code will be added to add additional fields on checkout page. When order will be placed, the values of additional fields will be saved as custom fields in database.
1) Should these additional fields be mandatory or optional on checkout page?
2) After the order is placed, should the values of these additional fields be displayed on following pages: customer "order thankyou" page, customer panel "view order" page, customer "order details" email, admin panel "view order" page?
I have much experience in working on projects, using PHP, full stack development, wordpress, woocommerce. Your work will be done, according to requirements.
Thanks.