From Guild Wars 2 Wiki
Experience Scroll is a consumable that increases the character's level to 20 if that character is below level 20. It is a reward from Massive Achievement Chests received as part of the achievement rewards, and is also a birthday gift.“
Double-click to advance a character to level 20.
Can only be used by characters under level 20.
— In-game description
- There are two variants of this scroll. One variant is from achievement chests and the first birthday and another from the second birthday. While they stack with themselves, they cannot stack with each other.