Beans used for espresso are coffee beans selected and roasted for a particular preparation or style. Espresso is the brewing method, not a separate plant species. A bag labeled for espresso may be a blend or a single origin, and it need not be roasted to the darkest possible color to work in an espresso machine.
Ask what the roaster intends the coffee to do: taste balanced as a short drink, remain clear in milk, or present a particular origin character. Arabica and robusta can play different roles in blends, but a species label or a thick crema does not establish a complete quality ranking. The actual coffee and recipe still need to be evaluated together.
Choose a grind and dose suitable for the machine and basket, then measure the beverage and adjust deliberately. A fixed grind instruction cannot be transferred without context between different types of equipment. Whole beans offer the ability to make those adjustments when you have an appropriate grinder. The useful purchase is a coffee that supports your intended drink and routine, not merely a bag carrying the word espresso.
The conversation
A good question can make a better brew.