Select Home > Messages.
Click the Create New Folder button.
Add a folder name.
Click Save.
Select Home > Messages.
Click the folder you wish to rename.
Click on the 3 vertical dots to the right of the name.
Select Edit.
Rename your folder.
Click Save.
Once a folder has been deleted, it can't be restored. Proceed with care.
Select Home > Messages.
Highlight the folder you wish to delete.
Click the 
to the right of the folder name.
Select Delete, then click OK when the "Are you sure you want to delete the [Folder Name] folder? Any messages inside this folder will also be deleted" pop-up displays.
Click Delete again.