I am a user with full control of a Sharepoint site, yet I am having difficulty deleting certain columns from lists. I have a list that had the template migrated from another Sharepoint list. I confirmed that some of the lists in the new site have columns
that were used in the old site, but are no longer being used, and would like to delete them. Strangely, I cannot find the option to delete any of these columns.
This is a screenshot of the view settings with columns I would like to delete: 
But I cannot find any of these columns in the list settings. Here are the list columns for the same list: 
It's possible the Rentention label is a Sharepoint default column and shouldn't be deleted, but I know for sure that AnnualNotice_Email and ItemPermissions AnnualNotice are Sharepoint workflows that are running in the original list (just not sure why they
are duplicated). I've checked in the list workflow settings, but the workflows do not exist:

I'm trying to delete these columns but with no success. Am I missing an area during my search?