I don't know what is the difference between using "I have got" and "I have"
He's got broad shoulders.
Is it possible to say:
He has broad shoulders.
If yes, so what is the difference?
They both mean the same thing, but, in the context of formal writing, stick with the second one. If you are writing a résumé, for example, you would want to avoid statements like:
I have got six years of experience programming in Java
and if you were requesting some vacation days next month, you wouldn't want to begin an email to your boss with:
I have got a wedding to attend next month...
Instead, it would be better to write:
I have six years of experience programming in Java
I have a wedding to attend next month...
In casual conversation, though, it would be considered acceptable to use the "got" version – but you still wouldn't want to overuse it.
I was always told in school to avoid "got" wherever possible in writing. Nowadays though in international schools and in English classes in foreign schools out of the UK, all the lessons use and overuse "got". It really jumps out at me because I don't consider it good written English. In my opinion it is alright to use it colloquially when speaking but it is an ugly form of written English and usually quite superfluous. "I have a new dress" is far more elegant than "I have got a new dress".