Albino insects of any kind is supposedly impossible, and I've never heard or seen of a legitimate one yet. I've only seen a "white" body in any insect (mantids included) shortly after them molting (before they fully harden and dry).
No idea of the species - as the "normal green mantis" could be dozens in the USA alone as green is found in any species. Let along over the whole globe, as you have no location specified or set. If you are in the US, then the more common species found are the Stagmomantis carolina, Tenodera sinensis, and Mantis religiosa. Although there are many very similar species with only subtle differences.
To get a identification though, several photos will be required. If you are having issues uploading here (you have to use a computer as phones/tablets have problems) then upload to a free image host site and just paste the links for them to show - for example I use
PostIMG.org.