Mick's Instructions:
 
     How to Securely Send Credit Card Information to Mick's Macs

Step 1: Create a new document with your credit card number, name on the card, expiration date, and the security number. Save it to your desktop.

Step 2: Create a new folder on your desktop, and name it "Credit Card Information" or whatever you would like to call it.

Step 3: Move the document with your credit card information into the folder you have just created.

Step 4: Open "Disk Utility" by searching in Spotlight at the top right corner. (Icon looks like a magnifying glass)

(Inside Disk Utility)

Step 5: From the "File" menu select New > and then select "Disk Image from Folder..."

Step 6: Select the folder "Credit Card Information" that you just created. It is on your Desktop. Make sure to select the folder, and not the files inside the folder.

Step 7: Name your Image (We will name it the same thing as the folder,) and save it to your Desktop.
     -Important!- Where it says "Encryption," select "128-bit AES Encryption (Recommended)" or else your disk image will not be secure!

(Your window should look just like this before you click Save)

Step 8: Select a password for your encrypted disk image. Write it down!
     -Important!- Make sure that the box is UNCHECKED where it says "Remember password in my keychain" or else your file will not be secure.

Step 9: Next, open Mail, and start a new message to Mick's Macs. Find the newly created "disk image" on your desktop. It will be called "Credit Card Information.dmg" and simply drag it into the email. When you're done, click Send.