Skywrite

Source: Xanathar's Guide to Everything, DND 5e Wiki

2nd-level transmutation (ritual)

Casting Time: 1 action

Range: Sight

Components: V, S

Duration: Concentration, up to 1 day

You cause up to ten words to form in a part of the sky you can see. The words appear to be made of cloud and remain in place for the spell’s duration. The words dissipate when the spell ends. A strong wind can disperse the clouds and end the spell early.

Spell Lists: Artificer, Bard, Druid, Wizard