's

No. It’s is a contraction of it has. Gotta is not a word, so the sentence should read It’s got to be blue, It has to be blue, or It must be blue.

Gotta means have got or has got (to)(a) ,so I think is should be It gotta be blue.....could u explain more?

Thanks in advance

bmojtabaGotta means have got or has got (to)(a) ,so I think is should be It gotta be blue.....could u explain more?Thanks in advance

No, it doesn't.
"gotta" is a contracted form for "got to" not "have got to."

I've gotta go = I have got to go = I must go.
You'll hear "I gotta go" but that doesn't mean that "have" is part of the contraction.

so 's here is apostrophe or has or is???

bmojtabaso 's here is apostrophe or has or is???

AG told you yesterday - it's = it has.

SO in formal & standard English it should be 'It has has got to be blue' or ' It has has to be blue' or 'It has must to be blue'

Is it correct???

No.

It has (got) to be blue.
It must be blue.

And has got is simple present or present perfect here???

bmojtabaAnd has got is simple present or present perfect here???

It's technically the present perfect of GET but, for practical purposes, we treat it as a present tense equivalent of HAVE

I am really thank you for your replies....

I mean 'gotta' means 'got to' and when we say 'I gotta go' it means ' I have to go',so why cant we say 'It gotta be blue' instead of ' It's gotta be blue' because gotta means has to in the second sentence

thanks again for your kind of attention