Your Outlook.com password is the same as your Microsoft account password.
Go to https://account.microsoft.com/security and select Change Password.
As a security measure, you might be prompted to verify your identity with a security code. Decide if you want to receive the security code by email or phone. You'll be asked to verify your email address or the last four digits of your phone number, and then select Send code. When you receive the code, enter it and select Submit.
Enter your current password, enter your new password, and then select Save.
Go to the Microsoft account password reset page and follow the prompts.
If you think your Outlook.com has been hacked, see My Outlook.com account has been hacked.
If your Outlook.com account has been blocked, see Unblock my Outlook.com account.