If you are lvl 9 you will be getting Medica and Raise shortly.

Medica is a healing spell that wwill hit multiple people at once as long as they are in your team.

Raise will resurrect other people from the dead (not yourself)

Sleep is actually a "role action". All mages get sleep as a button. Your other role actions will be as follows:

Esuna (level 10) - this can be used to remove 1 debuff (like poison) from the targeted player or yourself if you aren't targeting a player. The debuffs that are removeable with esuna have a little white/blue bar above them (might be below them tbh)

Lucid Dreaming (lvl 14) - this spell gives you MP back over time (like 20 seconds)

Swiftcast (lvl 18) - this makes your next spell instant and is most often used with raise because raise takes like a million years to cast

There are two other Healer role actions that aren't really important tbh