If a minor (anyone under 18 years old) wishes to receive a piercing they will need:
Their parent or legal guardian to be present for the whole appointment with a valid form of ID.
Their birth certificate (you can bring the actual document, a legible photo on your phone, or a scan as long as that scan does not have the “void” watermark or other language that says the document is not legitimate as a photocopy/scan). There is no document that can replace a birth certificate.
If the minor is 13 years old or older, they will also need to bring a valid photo ID (like a passport, driver’s license, learner’s permit, or school ID). This is not necessary if the minor is 12 or younger.