for sage mode in general to be obtainable they should atleast be (not an uchiha or don't have curse seal)
For Dragon Sage users they need to find Ryuuchi cave and for Frog sage users they should find mount myoboku
Sage mode itself is the perfect fluxuaation of gathering chakra
you can only obtain one type of sage mode and to obtain sage mode you need to make a contract with frogs or snakes at their respective maps
for users to get perfect sage mode they need to have 100% natural energy . The user must stay still long enough for sage mode to complete for it to be perfect if they however move at 60-75% natural energy they will break the concentration thus making their sage mode imperfect
perfect sage mode=bigger boost
Imperfect sage mode=full boost
For Frog sage
Frog Kumite taijutsu skill
the user will have increased taijutsu both in damage and in range
the user can attack a tile away now and when up close and personal can knock back the target
Senpou Oodama rasengan a bigger and much more powerful rasengan
Senpo Rasen shuriken
a rasen shuriken that can be thrown and aoes when it hits
Dragon sage
Senpō: Hakugeki no Jutsu
the user fires a projecitle dragon wrapping around an orb that causes paralyse damage