Has Or Have?

Both are wrong. You need something else as the subject. For example: I have a mathematics class tomorrow. Or: I have math tomorrow.

CB

then how am i suppose to ask question tommorow has/have class?

Maximus69then how am i suppose to ask question tommorow has/have class?

Is there a math class tomorrow? Yes, there is one in the afternoon.
The construction of "there is" for a statement and "is there" for a question is frequently used to express the existence of something. i.e. There are people in the world who still don't know we landed on the moon four decades ago.

Do you want to ask "will there be class tomorrow?"

yes.how to ask?

"Will there be class tomorrow?" and "Is there class tomorrow" are both okay. You can also say "Do we/you/they have class tomorrow?" or "Will we/you/they have class tomorrow?"

why you use is ?Can i use are ? Example, Are there clases tommorow ?

Is there class? one class
Are there classes? -- more than one class.

Do we have class tomorrow? Do we have classes tomorrow? Do we have math class tomorrow? Is there math class tomorrow?