I want to teach to my magmar futur babies the move iron tail but I don't know which Pokemon can breed with him and transfert iron tail.
One of the ways to teach Magmar Iron Tail by breeding is teaching it to Lucario in Black and White 2 via move tutor then breeding it with a female Magmar. In X and Y just transfer the Lucario via Poke Bank then breeding it with female Magmar. Hope I helped! Source: Knowledge
What I would suggest doing is going to a Move Tutor and teaching it to a male Lucario, then breeding the male Lucario with a female Magmar/Magmortar. The reason for it having to be a male Lucario is because only males can pass down moves.
Source Source
Hope this helps :)