Refering to an automatic transmission, If you still have an ownsers manual, it will tell you to use Honda ATF-Z-1. This oil has since been upgraded to Honda ATF-DW1.
Changing tranny oil in these is very easy an recommended to do so thoroughly using a drain/fill procedure a total of 4 times.
I would recommend changing the filter as well.
I have attached 2 photos from my 2005 owners manual (pgs. 187 & 188) and this YouTube link
that is found to be very helpful but does not actually do the 4th drain/fill as described in the manual. (Note, the YouTube procedure is the same even though they are using a Honda Element.)
If you have a manual transmission, the YouTube video will not help you. Use Honda-MTF (Manual Transmission Fluid) and follow the procedure in the photo of page 188.