You can limit the amount of text that users can type in a text box. For example, on a survey form template, you can use this feature to prevent users from typing more than 500 characters in a comments box. You can design the form template so that the user's cursor moves automatically to the next control on the form after the character limit is reached.
Right-click the text box for which you want to limit characters, and then click Text Box Properties on the shortcut menu.
Click the Display tab.
Under Options, select the Limit text box to check box, and then specify the number of characters that you want.
To make the user's cursor advance automatically to the next control on the form after he or she reaches the character limit, select the Move to next control automatically when limit is reached check box.
Note: If you enable paragraph breaks for a text box, the character limit option will not be available.