Hi @eenatsios,
Welcome to the Trend Micro Home Users Community!
To answer your question, yes, Persona is legitimate and is used by LinkedIn for identity verification. They should erase your information once verification is complete. Verify the request through official channels and review LinkedIn's privacy policy or terms of service for details on how they handle your data. If you have privacy or data security concerns, you can contact LinkedIn's support for clarification before proceeding.
Hope this helps. Let me know if you need more help.