In general it is best to use a query as the Record Source for a form or
report, as you can sort the records and otherwise manipulate them (for
instance, combine FirstName and LastName, or perform calcualtions) to suit
your needs. In any case, a table should not be thought of as being in any
particular order. That's what queries are for.
You can use the form's Order By property, as suggested, but the query gives
you a lot of flexibility.