One of the menu options under the Contact Overview menu that is accessible when within a contact record is the Know Your Client section of the contact record:
After clicking Know Your Client, you'll then see the Know Your Client area for the contact and can begin filling in your applicable information for them.
Here, let's look at the Miscellaneous Personal Information section of this page:
If no data has been entered here, it will be blank as above. To add data, just click the Edit button in the top right corner of this section. You'll then see the below:
Most of the fields here are free form fields, but for Driver's License State you can choose from the dropdown menu and for DL Issue Date and Expiration you can choose a date from the Calendar to the right of the fields.
This area might look similar to the below once you've added your desired information:
This information is displayed upon, and can be added or edited from, the Miscellaneous Personal Information widget on a contact's Overview page.
Driver's License # and Expiration Dates are searchable from your Advanced Search page.
All of these fields can be included in any Custom Exports you establish.