|Acquire all 16 weapon abilities||Chapter 13||Skill Master Materia|
You'll be able to receive this Battle Intel once you reach Chadley in Chapter 13 and you'll need to advance the Main Scenario a little before you can complete it. When you can first access this, you'll only be able to acquire 14 however there are a total of 24 in the game (6 per character). Later in Chapter 13 you'll find two more weapons allowing you to hit 16 at the start of Chapter 14.
To learn a weapon ability, you must equip said weapon and use it in battle, making sure to connect with your target if possible and usually 4-5 uses is enough to master the ability.