Information fields allow users to add stats or quick information to a Lead's profile. To add new information or a new field to a Lead's profile, follow these steps.
Navigate to the Lead list (located on the left-side navigation bar, entitled "Lead List").
Find the Lead you want to tag and click on them (this will take you to their profile)
Click the “Info” tab
There you will see the “Info” box. Click on the white + button in the upper right corner of that “info” box.
There you can name the field and input the information. Once you have that done, click create.
The field will then appear in the “Info” area of the Lead profile.
Note - once you create a field in a Lead's profile, that field will appear in all Lead profiles.