date validation

We are trying to add validation rules in our consuming application. Could you please share what are the validation rules ( Max length, format) on the phone number that we use for authentication (please see the screenshot attached) ? 

Hello,

In Java, I would like to add a new field where the signer should fill in a date (in a date format DD/MM/YYYY).

• What type of field should it be?
• The signer should be allowed to add either the current date or one from the past. Not a future date. Is there any way to validate it and show an error message in case the validation is not passed?

Thanks,

Michail