Combo 247 is most likely an arbitrary name that Access assigned to the combo
box. The Row Source continues beyond what you can see. To look at the rest
of the Row Source, right click on the text and select Zoom. The Row Source
is expressed in a SQL (Structured Query Language) statement. SQL, very
briefly, is a database computer language for managing data in relational
databases.
The window where you can see the Row Source, name of the combo box, etc. is
called the Property Sheet. For another way of viewing the SQL, click the
Row Source on the Property Sheet, then click the three dots to the right of
the row. You will be presented with a query design grid, which will tell
you among other things the table (or tables, maybe) used for the Row Source.
You can edit this query. If you save it you will be prompted to give it a
name. If you give it a name, that name will become the Row Source. It is
the same SQL, but it is stored as a named query. If you do not save it (or
if you give it a name) you will be asked upon closing it if you want to
update the property. If you want to change the Row Source, click Yes. In
any case, you can view the query results before saving it by clicking View
With the query open you can also click View >> SQL to look at the SQL. If
somebody asks you to post the SQL, this is how you find that information.
As I said, you can change or edit the Row Source, but I can't be more
specific without knowing more about the SQL, and maybe something about your
project's structure. It may be more than I can get into here if you are
just starting up the learning curve, but there is information available that
will help you find your way around. One source of information is here:
http://allenbrowne.com/tips.html
In particular, see the Tips for Casual Users. Crystal's Access Basics is an
excellent overview; the other links tend to be more specific. There is also
a Links link on the right side of the page. There are many other resources
there.