When you're creating a shortcut, you can add variables that will automatically fill in with the real data when you use the shortcut in a ticket. You can use these variables in Private comments, Public comments, and in the title.

The plus icon will add the the title variable in the value field.

When you type {{ you'll see a list of available variables that you can use.

Once you hit a shortcut with variables in a ticket, they transform into their actual values.