>How do I include quotation marks (" ") in the code below, so that the value of mGroupNumber is stored as "X09" instead of just X09 for example. (mGroupNumber is declared as a Character).

mStuffIntoGroupNumber = [update License set GroupNum = "] + ;
  alltrim(mGroupNumber) + [" where recno() = ] + ALLTRIM(STR(mRecordNumber))

Or even simpler with TextMerge

TEXT TO mStuffIntoGroupNumber TEXTMERGE NOSHOW PRETEXT 7
update License set GroupNum = "<<alltrim(mGroupNumber)>>  where recno() = <<mRecordNumber>>
ENDTEXT