Prefixes (or Tags) are text that is displayed prior to the caption. 

For example, Prefix/Location 1 has different types of building names. Select a building name, i.e. Dwelling, and then select the caption "Front Overview" and the text that will be copied to your computer's clipboard is "Dwelling : Front Overview".

Now, select the next caption card "Address Verification" and the complete caption will read, "Dwelling : Address Verification".

You can add 4 prefixes to make an entire caption read something like this: "Dwelling : Main Level : Bathroom : Ceiling : water damage to drywall on ceiling".

Each prefix is optional so you can mix and match as needed.