create a form with a text box and a submit button.
the text box will be for entering the email address, make note of the name of the text box.
create a recordset that will query the users table. in the filtering section select the email address column, select the Form value filter type and enter the name of the text box next to it.
in universal email, set the too address to use the email address column from the recordset. for the email body, click the DW Edit icon, from the bindings panel, expand the recordset and use the bindings for the user name and password column to add that information to the email.