Eagle Tattoo
On Styles' right arm, he has an eagle tattoo covering what used to say "Things I can." He covered the old tattoo a couple years ago but hasn't opened up about why or why he chose an eagle specifically. Though it feels easy to assume the eagle symbolises freedom, it's hard to say for certain.
"Mary" Tattoo
Above the eagle is the name Mary, Styles' grandmother.
Palm Tree Tattoo
Styles has a palm tree tattoo on the back of his right arm, and while I don't know for certain why he got it, I do know his sister has the same tattoo.