First, please ensure that the email address entered in Opfin for the new employee or contractor is accurate. Typos in the email are the most frequent reason for this problem.
It is also possible that your email provider is blocking the emails from Opfin and marking them as spam. Please check your inbox and spam folders carefully for the email. The organization administrators can also re-trigger a welcome email from the employee's profile page.
One more option for the employee is to go to the Opfin login page, and click on the "forgot password?" link to send themselves a password reset email.