Which permission level allows for the addition of a folder or editing of a file?

The permission level that allows for the addition of a folder or editing of a file is "Allow- Modify." This permission level is specifically designed to provide users with the ability to read, write, and delete files or folders within a given directory. It offers the necessary capabilities for making changes, such as creating new folders, modifying existing files, and saving those changes.

In contrast, the "Allow- Write" permission only enables users to create and edit files but does not grant them the ability to delete or view the existing files in that directory. "Allow- Read" strictly restricts users to viewing files without making any alterations. "Allow- Full Control" does encompass modifications but includes additional privileges that may extend beyond what was asked, such as changing permissions or taking ownership of files and folders.

Thus, "Allow- Modify" is the most appropriate choice for the specified actions of adding folders and editing files.