i have a microsoft account to but i want to change my username but i dont know how because it requires password but idk my password. (im using microsoft account i think.)

To reset your password from the launcher, select "Go Back" to return to the login selection screen, and follow the prompts to login with a Microsoft account. After entering your Microsoft email, you'll see a 'Forgot Password?' link.​ ^FF

i think microsoft account because on the top right, it says microsoft account and some words and numbers.