In query design view, I think you are looking at the properties of a field.
Is that what the title bar of the Properties box says?
Try clicking in the upper pane of query design, away from the tables.
Alternatively, switch the query to SQL View (View menu), and add the word
DISTINCT right after SELECT. It will then read something like this:
SELECT DISTINCT Field1, Fieldname2, City, ...
If the records have different addressee names, and you include those names
in the query output then you cannot de-duplicate the query like that
(because the output fields are not duplicated.) You are trying to collapse
records into one based on the address. You could write some VBA code to
concatenate the names, and add that to the de-duplicated query, but that
would not really be worth the effort because a slight difference in an
address would spoil the result. For example, if you have a records for Fred
Jones at 14 First Avenue, and for Freda Jones at 14 First Ave, the addresses
are different and so the code would not combine them.
The real solution is to actually create relationships between the people,
and then choose which client to send the mailing to: the household (with its
Addressee name), or an individual in that household. This is the correct
relational design, avoids the problem or slight differences in spelling,
actually defines the kinds of relationships that exist, and provides for
reliable addressing. For an example of doing it like that, see:
People in households and companies - Modelling human relationships
at:
http://allenbrowne.com/AppHuman.html
The article includes a downloadable sample of how to design the interface,
and describes how to assign individuals and households to mailing lists.
None of the alternatives provide the power and reliably of doing it
correctly like this.