Fire Emblem: Three Houses - How To Change Outfits
Fire Emblem: Three Houses doesn't give you many options for customizing its main character, Byleth. You can choose Byleth's gender and his or her birthday when you start the game. That's more or less it. However, if you know where to look, you can give Byleth a change of clothes once you get past the opening stages — although Fire Emblem: Three Houses doesn't do a very good job of explaining how.
After you play through the prologue and choose which one of Fire Emblem: Three Houses' factions you're going to lead, you'll get one day at the end of every in-game week to roam the Garreg Mach Monastery and talk to your students, go fishing, tend your garden, and so on. That's when you can change your clothes. Your journal is on the small desk in your quarters. Walk up to it, hit "A," and style Byleth in his or her finest.
If that's not working for you, there are two possible reasons why. Originally, the ability to change outfits was unlocked much later in the game, so make sure that you have the latest version of Fire Emblem: Three Houses installed on your Switch. In addition, the ability to change clothes is only available if you actually have other outfits to put on. If it's early in the game and you didn't purchase the Fire Emblem: Three Houses Expansion Pass, you won't have any other clothes, and the option won't appear.
Halfway through Fire Emblem: Three Houses, a major plot twist will unlock some new looks for your students. After that, if you start a new campaign using New Game+, you can change your students' outfits (and hairstyles) in addition to Byleth's. We won't get into spoilers, but trust us: you'll know what we're talking about when you see it.