magento2 – How to get the value of a field on the cart page in magento 2

how are you ?!

Well, I would like to know if there are any observables that I can observe on the cart page. Or if there is a way to capture the value of a custom field that has been inserted.

Explaining further, a field was added and I would like to have access to this data when I start the checkout (delivery address)

Can anybody help me?