You need at least two hands to use a bow, regardless of its size. A longbow is too unwieldy to use while you are mounted. If you have a penalty for low Strength, apply it to damage rolls when you use a longbow. If you have a bonus for high Strength, you can apply it to damage rolls when you use a composite longbow but not a regular longbow.
| Range | Damage | ||||||
|---|---|---|---|---|---|---|---|
| Weight | Cost | Damage | Critical | Increment | Type | Special | |
| Longbow | 3 lb. | 75 gp | 1d8 | ×3 | 100 ft. | Piercing |
Source: Player’s Handbook (Page 119)