If I sign a contract then am I obligatory to join that job? Can company take any legal action against me or no?

Generally you are not obligated, depending on what it says in the contract. If you accepted any moving, airfare, or other expenses or perqs, then the company would have recourse to recover funds.

You need to read the terms of the contract. But an employment contract is usually not binding. But, as noted, any advances paid you in terms of bonuses, relocation etc. would have to be reimbursed.

... But an employment contract is usually not binding. ...

It's binding, but it's what we call an "executory contract". This means that the company's duty to pay the employee's salary comes into effect if and when the employee puts in some work. But no, the employee cannot be forced to go to work. Not since the enactment of the 13th Amendment, at any rate (asuming OP is in the U.S.).