When you create a custom field, it is automatically added to your list of dynamic tags to use in messages.
Dynamic tags transform a message from a cookie-cutter mass text to a personalized message.
To use a custom field as a dynamic tag you will first need to...you guessed it... create a custom field. Find out how here:
If you already have the custom field you want to use as a dynamic tag. Start by creating a message to see what it will look like.
The dynamic tag for your particular custom field will appear under the same name. As you can see below, I used a dynamic tag named "Delivery Area."
This is what my message would look like as a preview to my contact John Doe.
Pro tip: if you want to use this message again, select "Save/Update Template."