Outlook.com users can change their password using the option provided as part of the Managing your account settings.
Step 1: Login to your Outlook.com account and click the Settings icon available on top right hand corner.
Step 2: Select More mail settings from the Settings drop down list.
Step 3: In the Outlook.com settings page, click the Account details (password, addresses, time zone) under Managing your account.
Step 4: Click Change password link available under Password and security info.
Step 5: In Change your password screen, enter the current and new password for your Microsoft account. And if you want the password to be changed for every 72 days then mark the checkbox with caption as “Make me change my password every 72 days”. After making the required changes, click the Save button.