how to make the configurable list widget field text box in alpha numeric validation and also to ensure the maximum number validation?

Hello swapna_summit,

Unfortunately, it is not possible to do any alphanumeric validations for the configurable list text boxes. The only option currently available is to validate a numeric input value. 

Do get back to us if you want to send a feature request to our back end team and we will do the needful.

Thank you!