This code adds a date of birth calendar picker to the checkout so customers can enter their birth date before checkout. They can enter their D.O.B with or without entering their year of birth.
The customers D.O.B is printed on the order details screen for admins and saved in the database for easy usage.
Install the zip folder as a new plugin or copy and paste the PHP code to the end of your child themes functions file or custom code snippets plugin.
These solutions may also help :