How to exactly to use till/untill

I was reading an article, where it in which was written- They will NOT arrive until Tuesday.

Will somebody explain why, that if I write it like 'they will NOT arrive till Tuesday' that is write right or wrong, and if wrong why? Thanx

'till/until' means 'up to', 'as late as', 'up to the time of'.  They will not arrive until/till Tuesday.  They will stay until Friday. 

I am almost certain you omitted or didn't see the word NOT in there, otherwise no one would write 'until' in such a sentence

How to exactly use till/untill

I Was reading an article, where it was written- They will arrive until Tuesday.
Will somebody explain that if I write it like -they will arrive till Tuesday.
It is write or wrong, if wrong why.? Thanx

I was reading an article, where it was written- They will arrive until Tuesday.
Will somebody explain tell me that if I write it like this -they will arrive till Tuesday.
is it write right or wrong. If wrong why.? Thanx (This is spelled thanks, but I think you are using the slang form on purpose, which is fine.)

Both words, till and until, mean exactly the same thing, and are 100% interchangeable. Just use whichever you prefer, or whichever you feel fits the sentence better. Also, the sentence "they will arrive until Tuesday" does not make sense. If it said "they will NOT arrive until Tuesday", it would mean that they would not arrive before Tuesday. If this is the case, you can say "they will not arrive until Tuesday" or "they will not arrive till Tuesday" and it means exactly the same, and both are correct.