OK, let's back up, maybe there's a terminology problem here
In Word there are 'headers' (and footers) that repeat on every page. These
are set up in a separate view, often contain page numbers. But you don't
need to touch headers to get the heading row of a table to repeat.
Word also often refers to 'headings' - paragraphs in one of the built-in
styles Heading 1, Heading 2, etc. These aren't relevant to tables and
repeating rows either.
The title of a table is usually a 'Caption' - that's also a paragraph, and
there is no easy way to make it repeat on follow on pages (though there are
various workarounds).
But if you are really talking about the first row of a table, containing the
column headings, then the setting you need *is* heading rows repeat, which
is available from the Table menu. You can select one or more rows (but they
must all be at the top of the table), and you can see whether the setting is
on or off by the check mark beside the menu entry. Or use Table > Table
Properties and look at the properties for the row.
Note that the headings will only repeat if the same table runs over the page
boundary - if you have split the table (you can see this if you Show
paragraph marks - there will be a paragraph between the two parts) then
obviously the second table won't show the headings from the first.
Hope this is some help in sorting out what is going on.