As Harry Potter Wizards Unite takes place in the universe of Harry Potter - you can choose the magic house of your hero. All four houses known from Harry Potter universe are available: Gryffindor, Slytherin, Ravenclaw and Hufflepuff. It's up to you where your hero gets to.
Does the choice of house affect the hero and his story?
No, the choice of the house does not affect the character. It does not affect the plot of the game and the relationship with other the characters. This choice is purely cosmetic. It doesn't even have an impact on your avatar - which means that when being in Hufflepuff you can have Gryffindor colors on your avatar.
How to choose a house?
To change the house you must enter the "Ministry ID". ID can be opened by clicking on the icon shown in the screenshot above. Then, click on the house icon.
When a new window appears, you can simply select a house. This has nothing to do with your character, and in addition, the house can be changed at any time of the game.