Let me take a stab at this and guess that you're starting with Letter-sized
card (11" x 8.5") and folding across the short dimension? I prepared a
similar thing: a Christmas Card from A4-sized card. There was some
trial-and-error involved - I didn't go looking online for templates, I
decided on a d-i-y approach. I don't have a duplex printer so two pages are
required for inside and outside surfaces.
To begin with, I needed to divide the page into four, in order to position
text and/or pictures correctly when folded. I found the centre of the page by
drawing two straight lines from corner to opposite corner (I used the Line
tool on the Drawing toolbar). Then I drew horizontal and vertical guide lines
through the centre point, and then deleted the diagonals. This is repeated on
the second page.
Depending on the orientation of your page in Print Layout View, you may have
to change the Text Direction (Format menu). I have Landscape orientation set
so the top of the card is on the left of the screen, and the text direction
must run "bottom to top". Insert a text box into the right half of the first
page (this will be the front of your notecard). I left a 0.5" margin to the
edge of the card (and the relevant guide line).
You might choose to have the text box fill only the left half of the front
face of your notecard and put a picture with a caption in the right half. Use
the guide lines to position your content.
Any text that appears on the back of the notecard (the outside, that is)
will have the opposite Text Direction set.
Insert text boxes on the second page in a similar way. Some trial and error
may be required to get the Text Direction correct on this page, or to feed
the card the right way round after the front face has printed.
Fold and admire!