It depends on the legislation of the country. There is no single answer, what may require more than one executive in one country may not be true elsewhere.
advantages of executive
Opponents believed having a single executive was just like having one king.
the argument for and against having a single executive was that they thought a single executive could act more quickly when urgent action was required.
Plural executive means that there are more than one person serving as the chief executive of the polity. For example, the old USSR at one time , had a troika - three persons who made administrative decisions. Ancient Rome has a tribune system (prior to Caesar) in which two tribunes administered the state.
Virginia plan
executive agreement executive agreement
a single administrator.
the president
Egypt is a single country.
Executive Branch
the executive branch make sure the laws of the country are obeyed