If someone overstayed on USA visit visa and left the country voluntary now 10 years has been gone, can they can apply for visa again?

Your specifics in the case should be reviewed with an immigration attorney who might be able to help you. Your question is too broad and does not have enough facts to consult you at this stage.

The issuance of a visa is discretionary, not mandatory. This means that a visa can be denied for any reason and sometimes for no reason at all.

Yes. You can apply for another visa after the 10 years have passed. However, if you already have a history of overstaying your authorized status, then it becomes unlikely that the consulate will issue you another visitor visa.

The bar on entry into the U.S. means that an American consul *cannot* give you a visa until you live outside the U.S. for 10 years. After 10 years had passed, the consul* can* give you a visa - but *does not have to* do so. Nowadays, visa is a privilege, not a right. You have to convince the consul that you will not overstay your admission in the U.S., will return to your country, will not accept employment unless permitted, will not be a danger to public safety and national security, and will not require financial support from the public funds. Apparently, you did not convince the visa officer in all of this.