php validation issue

This is a input in php form

core::config(‘advertisement.tos’)))?>”>

I am unable to understand what “tos” is and how to fetch it.

I added another input box here

core::config(‘advertisement.tos’)))?>”>

Question
How do i store the checked, unchecked value into the db (YClass open source software) and also validate that the box is checked? Also, I want to display the text that they accept as text on the rendering page

thx

Himani tech bag