It's been years for me, but I remember it being my friend could grant me one level for every two levels he had. You have to be logged it at the same time and standing near each other (at least you had to then).
For every two levels a recruit player gains, they can grant one level to a character on the original player's World of Warcraft account.
The recruit must log in to the character with grantable levels, right-click the friend's character portrait, and select Grant A Level. The Grant A Level menu item will only appear when:
-The characters are in a party on the same realm and faction.
-The characters are within 100 yards of each other.
-The character granting the level is higher level than the character receiving the level.
-The character receiving the level is level 84 or lower.
-The character receiving the level has not disabled experience gain.
Note: All grantable levels must be used before the 90-day Recruit A Friend link expires. Unclaimed levels are not moved during a character copy or transfer. Be sure to use them before you transfer.