It may be legitimate. See the information in Verify your identity for Apple Card or Apple Cash - Apple Support
including the "Why you're asked to verify your identity" section of that support article.
Also see the information in Legal - Apple Cash and Apple Payments Inc. & Privacy- Apple inlacing the following excerpt:
Verifying Your Identity
You may be asked to provide information, including your name, address, and Social Security number, to the bank and their identity verification service provider to verify your identity and to comply with banking regulations. Information you provide to verify your identity will be used only for fraud prevention and to comply with United States financial regulations. Your name and address are securely stored by the partner bank and Apple Payments Inc. If needed to verify your identity, you may be asked to provide additional information, such as date of birth, answers to questions (for example, confirming a street name you have previously lived on), or a copy of your government ID. This additional information cannot be read by Apple Inc.