Its from Mexico Gov
Starting from January 1, 2025, the Mexican government requires the collection of RFC (Registro Federal de Contribuyentes) tax numbers
for orders sent to Mexico.
Also known as
Mexican Customs will officially launch verification of recipient's personal tax number on January 1, 2025
Here is What RFC Form
RFC： Composed of 13 characters, the format is 4 letters+6 digits+3 letters/digits.
You can fill it in the check out page
THANK YOU !!!