Till is used in a more informal way.
E. g.
Until is a formal term compared to till.
E. g.
Till and until are both separate words, till is not derived from until and it is incorrect to spell it as untill.
E. g.
Until and till both show time. They cannot be used to talk about distance. Instead we use 'to', 'as far as' or 'up to'.
We walked as far as the edge of the forest. (NOT We walked until the edge of the forest. )
To talk about quantity we can use 'up to'.
This car can seat up to eight people. (NOT This car can seat until eight people. )