The Hindi and Urdu are the same spoken language.
The main difference is that Hindi is mostly
spoken by Hindu's in India and Urdu is mostly
spoken by Moslems in Pakistan.
Kind of like comparing English spoken
in Canada to English spoken in the USA.
They are more or less the same.
The Hindi language is written in the alphabet called Devanagari. The Devanagari alphabet is also used to write several other languages in India including Sanscrit.
Urdu is written in an alphabet called Nastaliq which resembles the Arab alphabet. Again probably because most people that speak Urdu are Moslems.