What difference between “二”and “两?

When you want to say numbers you just say 二 for example if you are telling you phone number you can say 我的手机号码： 2229456（二二二九四五六)
or if you want to say second floor second word etc you should use 二 ： 第二层，第二词......
But if you have a mesure word after number two you have to use 两：
两本书，两个人......

二 - 号码 - 2 号 ， 电话号码。。。
两 - 数量 - 两个苹果，下午两点。。。

here is the detail in the dictionary
https://www.cchatty.com/grammar/10307

”二“ is generally for numbers (counting：一二三)
“两” is used as a measure word (you have two of something：两瓶水)