Within Teamwork Projects, if you have a user who is unable to log in to their account, you can send them a new invite where they will then be able to create a new password.
To do this, first go to the People area of your site:
In the top right corner of the People list, click the options (three dots) button, and select 'Send Invites' from the dropdown menu:
In the Send Invites modal, select the 'Resend Invites' tab, where you can choose from a list or search for the user's name.
Tick the box beside the user's name and click 'Send email invite now':
Once the invite has been sent, the user will receive a link where they can set/reset the password they wish to use for accessing their your Teamwork site:
For more information on resetting your passwords: Changing your password