How do I add a validated field to my shopping cart?

[adrian56]

Hi everyone!
I need to add a field like this on my store page, with additional validation up to 10 digits, could someone help me to create such a field?
Thanks in advance for any hint

[zaczee]

HI,

We can add additional field by customizing the cart.liquid file

[adrian56]

Thank you! Could you help me to create such html code?