Baldur's Gate 3 has a huge array of character creation options, both in terms of visual changes and changes that influence gameplay. While it's been possible to change the latter since the game came out by speaking with Withers, patch #3 has also added a way to redesign a character's appearance and some other elements post-character creation too.
Baldur's Gate 3: How To Change Appearance, Voice, & Pronouns (Magic Mirror Location)
The Magic Mirror allows players to redesign many aspects of their character in Baldur's Gate 3, so here's how to find it.