At times you want to ask a user for private information such as a password or social security number. If the program is run from a place where someone might gain this information, you want the echo print to show some neutral character such as '*'. The PasswordChar is a property of the TEdit box that is set when you want this cloaked echo print. If this property is set to #0 in the Object Inspector or '\0' in a program, standard echo printing is enabled. Otherwise the echo character is set to the character you choose. You can ask the user if they want to see the information they enter and set the PasswordChar accordingly. Below you see the description of this property from Borland's help.
Use the PasswordChar property to create an edit control that displays a special character in place of any entered text. If PasswordChar is set to the null character (ANSI character zero), the edit control displays its text normally. If PasswordChar is any other character, the edit control displays PasswordChar in place of each character typed. PasswordChar affects the appearance of the edit control only. The value of the Text property reflects the actual characters that are typed.