Source: Tasha's Cauldron of Everything

Wondrous item (tattoo), common (requires attunement)

Produced by a special needle, this magic tattoo appears on your body as whatever you desire.

Tattoo Attunement. To attune to this item, you hold the needle to your skin where you want the tattoo to appear, pressing the needle there throughout the attunement process. When the attunement is complete, the needle turns into the ink that becomes the tattoo, which appears on the skin.

If your attunement to the tattoo ends, the tattoo vanishes, and the needle reappears in your space.

Fluid Ink. As a bonus action, you can shape the tattoo into any color or pattern and move it to any area of your skin. Whatever form it takes, it is always obviously a tattoo. It can range in size from no smaller than a copper piece to an intricate work of art that covers all your skin.

Disguise Self. As an action, you can use the tattoo to cast the Disguise Self spell (DC 13 to discern the disguise). Once the spell is cast from the tattoo, it can't be cast from the tattoo again until the next dawn.