One of the sections within the Know Your Client area of contact overviews is the Misc. Personal Information section, accessible by clicking the "Misc Client Info" tab at the top of this section:
To add or edit any information here, click the Edit button in the top right corner of the section. You'd then see the below:
The first two fields here are freeform text fields. For the last two you can choose from the options available when clicking inside the field.
This area might look similar to our original example above once you've added your desired information.