Creating fictional characters who actually simulate demographics, environmenyt, culture and needs of a real user helps to understand the end user and designing in their direction.
The more specific we are, the better we can understand the different scenarios of a user using our product. Whether they are professional, students, foreign language speakers, male or female, old or young, parents, married, single.
Simulation of a specific task that a user might want to do while using our product.
Use the Myers-Briggs diagrams to set user personalities. .