The duplicate exists to enemies as a physical clone, but can only grant advantage to the cleric in melee. It can move and speak independently or simultaneously at the clerics' discretion.

How many times can I use invoke duplicity?

At 17th level, you can create up to four duplicates of yourself, instead of one, when you use Invoke Duplicity. As a bonus action on your turn, you can move any number of them up to 30 feet, to a maximum range of 120 feet.

Does invoke duplicity take concentration?

Invoke Duplicity is a Trickery Domain feature that requires concentration and allows you to "cast spells as though you were in the illusion's space, but you must use your own senses."