To add offset dates, use syntax similar to the following:

{Task.RespondBy(-7d M/d/yy)}                            Subtract 7 days from the Respond By date
{Matter.FilingDate(+1m)}                                     Add one month to matter Filing Date
{Matter.FilingDate(+12m)}                                   Add one year to matter Filing Date
{Matter.FilingDate(+12MMMMM)}                         Add one year to the matter Filing Date and display the
full name of the month