How to write a vision [generally] for some business ? Is it have some template ? any example ? Business about online ticket services .
What is a 'vision'?
It's such a nebulous objective... I don't see how there could be a template. Unlike requirements specifications, functional specifications etc, there is no accepted understanding of what a 'vision' actually is...
I'd speak to the person who commissioned you to write the 'vision', and ask them what exactly they are trying to achieve and what their expectations are.
Here is a nice article on the Vision. Note that it doesn't have to be a heavyweight document (spend as little time as possible but as much as required). For more formal templates, RUP has some for the Vision artifact.
Karl Wiegers' book, Software Requirements, has an excellent template. I've used in for several projects. It seems a bit formulaic at first, but over the subsequent days and months, really helps a team keep focus.
http://www.amazon.com/exec/obidos/ASIN/0735618798/processimpact http://www.processimpact.com/books.shtml
The Business Motivation Model is a great source. They define what a business vision is, relate this concept to other relevant concepts in the organisation, and give good examples.
If you are interested in how business requirements are refined into user requirements and how, eventually, they determine what a software system does, you may want to have a look at the OPEN/Metis white paper.