I don't have the book handy to specifically check this, but...
Enderverse lists Rackham as Half-Maori while Wikipedia says Mazer Rackham is described in the book as a half-Maori New Zealander
This article confirms that the tattoos are meant to be Maori.
So while the book does not seem to ever actually specifically say that he has such tattoos, they DO make sense in terms of his character.
scifi.stackexchange.com/users/5184/phantom42
Yes, it seems to be added just for the movie.
I just searched a digital version of the novel.
Although the name "Rackham" appears 40 times, the word "tattoo" appears zero times.
Here's how Rackham is described the first time Ender meets him:
He looked to be about sixty, by far
the oldest man Ender had seen on Eros.
He had a day's growth of white whiskers that grizzled his face only slightly less than his close-cut hair.
His face sagged a little and his eyes were surrounded by creases and lines.
He looked at Ender with an expression that bespoke only apathy.
There's nothing about tattoos on his face, and that would be the moment to mention it.
scifi.stackexchange.com/users/1271/Pixel
SECOND UPDATE :
Found what could be considered canonical answer in a Marvel Comic ( Formic Wars: Burning Earth 01 ).
There, Mazer has no tattoos at all .
This should be considered canonical since Marvel's "Ender's Game" comics - including "Formic Wars" series - were done with Card's full cooperation and
were his idea, he clearly had some say in the way characters looked
We know that the comics were strongly affiliated with Card from first prequel book's Afterword, as well as the fact that they were directed by Card: To add to Pixel's excellent answer,
the prequel book ( Earth Unaware ) showed Lieutenant Mazer Rackham, and didn't mention any tattoos (UPDATE: checked against soft copy).
UPDATE:
Just read the second book in the prequel series ("Earth Aflame").
The books heavily centers on Rackham.
He was NOT described as having any tattoos.
However, the book goes into great detail of his background, which CAN be compatible with the tattoo theory:
His mother was Maori, his father English
His mother had to separate from the tribe because they objected to her marriage
As a result, until her death, she
**raised him fully immersed in Maori culture - language, legends, songs, warrior ethos, and all. After her death, his father raised him "full-on-Enhlish".
#3 means that it is quite possible that Rakham would have gotten Maori tattoos upon reaching adulthood, the age when Tā moko (maori tattoos) typically apply, out of respect for his mother's memory; but #4 means that it wasn't a certainty.
Again, the book doesn't describe any outward features (tattoos OR lack of thereof), the only physical description was weight and lack of fat (duh).
scifi.stackexchange.com/users/976/DVK-on-Ahch-To
The tattoos may be consistent with Mazer Rackham's Mom's ethnicity, but NOT with his character's preferences or work as represented in the books (though maybe he had meaningful tattoos somewhere discreet and invisible to the other characters?).
Mazer does extensive undercover work in Shadow of the Giant .
Hardly anyone who sees him suspects what a badass he is (including Ender, at their first meeting).
He seems to cultivate this stealthiness, which makes sense considering that at first his existence and then his continued presence on Earth remain classified.
His appearance needs to support that premise in order for that premise to work.
The facial tattoos are therefore IMHO not only not appropriate for Mazer's internal character but also actively take away his powers to do undercover work as well as being inconsistent with his storyline.
So basically they seem to be an arbitrary way for Hollywood to emphasize the "Mystic Native Life Coach" trope more than it was emphasized anywhere in any of the books, at the expense of the character's other dimensions.
I'm personally not so happy with the decision.
scifi.stackexchange.com/users/16046/Reader
While not truly authoritative, I found it interesting that official artwork for Card's short Mazer in Prison explicitly shows him without facial tattoos.
The art was apparently featured in Card's emagazine Intergalactic Medicine Show .
scifi.stackexchange.com/users/1359/Beofett
The first image of Ben Kingsley as Mazer Rackham  has surfaced recently :   I did not remember him described has having a tattooed face in the book. Is this an addition made to the character especially for the movie?
Did Mazer Rackham have a tattooed face in the Ender's Game book?
scifi.stackexchange.com
<movie><enders-game>
scifi.stackexchange.com/questions/35024
scifi.stackexchange.com/users/45/DavRob60
This seems to be added just for the movie.   The tattoos were added to the character solely for the movie.
The tattoos were added to the character solely for the movie.