To learn any jutsu you need to have the req BUT you also need to prefrom the hand seals for that jutsu once then you just can do it nay old time this doesnt include clan jutsus

but you also have to learn the seals from NPC jounins by preforming missions for them

You can also learn handseals from your jounin sensie where when you become a jounin you can have 3 genin in your party which you can teach them all handseals you know. also when one of your genin become chuunin you earn 10k yen