Currently, someone who has been convicted of fraud is able to become president.
Given that the basis of fraud is consciously and intentionally convincing others of lies, for the sole benefit of the perpetrator, and given that a fundamental foundation of our democracy are leaders who work for the country and the people and not for personal enrichment, a fraud conviction should be disqualifying.
In the event one was found guilty of fraud prior to running for president, they would be disqualified. Should the conviction occur after elected, but before taking office, the presidency would be transferred to their vice president. And, should the conviction occur while in office, they must be impeached.