Every class gets new feeats every three levels (1,3,6,9,12.....).
Only exeption is the fighter who gets not only feats at the levels mentioned above but also can pick a feat from this list=>
LORE: Fighter Bonus Feats every two levels (2,4,6,8,10.....)
That also means a fighter can pick two feats at level 6,12,18,24...
and here you find the classes with all automatic bonus feats listed :
LORE: ClassesHope that helped you and was what you looked for!
>Xirion>
Edit: Fighter is not the only one, wizzard can select a bonus feat every 5 levels. As far as I know these are the only exeptions