User Persona
User personas are fictitious characters that represent your target audience/user database.
I always create this before moving on to create a user journey or user flow chart.
Creating personas alone can be tricky but with the help of everyone on your UX team and the product manager/product owner, this could be the most interesting task.
Some other times, the persona creation could be the responsibility of the Product Manager. You should also know that brain wave could make for some changes in persona and design.
UX design progressive, by this I mean that as you make progress in your design process, changes may occur which you will need to consider.
To keep things simple, I'll advise you have these 4 items on your user persona:
1. Short Bio
2. Goals
3. Frustrations
4. A Quote
All of these four mentioned above will help you create a user persona with ease.