Mail merge tags allow you automatically enter in the first name/last name/email for any of your Visible contacts in an Update.
To get started, you will need to decide where you are going to use the mail merge tags. For our example, we want to customize our greeting to say "Hey [First_Name]."
First, highlight the text where you would like the customize field to show.
Next, click the tag icon to the right side of the editor, select what custom field you would like to insert (first name, last name, email).
Lastly, you'll be prompted to choose your fallback value in case the custom field does not have a value.
For our example in the screen recording above, we are changing the text from "Hey there" to insert the contact's first name instead of there.