You may have noticed that there is no visible password field in the user record. That is because the default method is to email the user an account verification they can use to set their password. However, if you do not have an email server configured, there is an alternative method for setting the user password.

After saving the user record, use the Change Password button at the top of the form.

A form will then appear allowing you to set the password for the user.

Now in Odoo 10, there is a far more visible button available at the top left of the form. Just click the Change Password button.