To add to your customized list of Job Log flags, go to the Main Menu > Settings > Account > Job Log. Only Admin users on the account will have access to this option.
Use the "Add New Flag" box to set up custom flags. Once added, new flags will show up on all current and future projects.
Existing flags can also be removed from this page. If a flag is deleted, you will be asked to reassign existing entries to a new flag.