If you have forgotten your Office 365 Password then please go to the Office Portal at https:portal.office.com
At the login screen select 'Can't access your account'
You will then be asked for your user id, this is the email address you have set up for the user. Once you have entered your user and confirmed the characters displayed in the picture, click 'Next'.
You are then asked by what means you wish to have a verification code sent to you. When you first signed in to Office 365 you would have entered a Telephone number and alternative email address. The verification code will be sent to either of these detonations.
I opted to have the code sent to my email, you will see the screen then progresses with the option to allow the input of your verification code. In my scenario I went to my email account, opened the email and copy and pasted the 6 digit code in to the box.
When clicking next, you are then asked for the second stage verification which this time I chose to have the SMS message sent to my phone number. And again you enter the code in to the box and then set up your new password.