What is the different difference between "need" and "want"?

1- want: expresses "desire"
use "want" when you want some thing not necessary
ex: i want to play football.
as you see football not necessary to play it ,and if you don't nothing will happen .

As you see, it's not necessary to play football. If you don't, nothing will happen.

note: you can say "want to" or "wanna"

Sometimes when English speakers say "want to" it does sound like "wanna." This is fine. However, when writing, this is not proper English.

2- need: express "necessity"
use "need" when you need some thing necessary
ex: i need water
as you see water is very necessary in order to survive

As you see, water is necessary in order to survive.

note: you can say " need to" or "need ta"

Never write "need ta."

Good job! You're exactly correct in explaining the difference between "need" and "want."