MacOS – What does the “Stationery Pad” option do

I use Hazel with an applescript to keep my filename extensions hidden. Hazel is just a way to make sure that anytime I create a new file, the applescript gets run on it. The applescript is pretty easy -- you can see all three lines of it in the screenshot below. I also like to set the color labels by file type, thus the selection of only PDFs and the red color labels. You can skip both of those if you like.

Just to be clear, you don't need to use Hazel. You could use folder actions or an automator workflow to initiate the applescript on the files you want to change.

Clicking the lock icon will prompt you for an admin password. After you provide it, the system will allow you to change the permissions for that file or folder in that "Sharing & Permissions" pane you see at the bottom of the Get Info window. This is a feature of the underlying Unix operating system that allows different privileges for a user, group, and others.

Note that you are always allowed to change permissions (whether the icon is locked or unlocked) when you (your user) is the owner of the file -- e.g. most of the files in your own user folder such as your Desktop and Documents folders. But when you are not the owner, you'll have to unlock this option to change the permissions.

There's a reason this feature is "locked" against casual access. It's not really something you want to touch if you're not very sure what you're doing. Messing with permissions can cause access problems, security problems, or both.

For more details, check out this Wikipedia article: http://en.wikipedia.org/wiki/Filesystem_permissions#Traditional_Unix_permissions