Macros is nothing but Templates in other sense. User can set pre define statements which can be used to reply to Customer in Notes to Customer or Message to the internal team members as Internal Notes.
User can add Marcos in the Admin Menu under settings Macros. By clicking on New you can add Marcos.
Macros on Update Ticket Page.
User can add Marcos by Clicking on Marcos button & selecting the right Marcos click add next to it.