Voting and Issues (or "Categories" in the non-political organizations) are populated by the RNC "Voter History" and "Modeled Issues". You can add custom values much like you would with the "Tags".
Voting history is under this tab. VH20G means Voter History 2020 General Election.
"A" = Absentee, "P" = Primary, "PP RA" = Presidential Primary - Republican - Absentee
Issues are RNC modeled issue this particular Voter is aligned with.
When creating an Audience, the Categories can be used to add the issues or voter history to target voters in addition to the other criteria. See "Filters"
Tip: After the initial upload of RNC data, and after an update of RNC data you need to synchronize the list with the contacts in your database. use the Up/down arrows to update the available Voting History and Issues categories.