Custom Form Field – Customised Form Error Messages

My developer has implemented a booking system using your plugin on my website.

In addition to creating the booking system, a form is also used which has 4x fields (i.e. Name, Email, Contact number, Postcode). They were created using “Custom form fields”.

If the fields are left blank and the user clicks the Submit button, error message appear that state “This field is required.”

Is there a way to customise these Error Messages?
Example:
Current error message: “This field is required.”
Proposed error message: “Please enter your name”

Appreciate any guidance. Thanks.