i have invitation. i need to know is this necessary to book the hotels and air ticket?

If it is the first time you apply for the business M type, you need to book the hotels and air tickets.

thank you sir. and can i write details on my company letter head about vist purpose and company profile?

If you are not CEO, then just ask your CEO to write that you (name and father name) are an employee, working so much of time past. You need to go for trading, checking or testing the items, something like that. Its Ok if a little profile of the company is written.
Just disregard if you know, that, you will also need Chamber and Commerce letter, banking statement etc.

Regards
Munir