A "record seal" is when you get a court order closing your criminal record for public inspection. With a record seal, you can legally answer that you have never been convicted of any crime on most job applications, etc.
Since you don't have any criminal record, you don't have any convictions and I am assuming no arrests. There is nothing to seal.
Record seals have nothing to do with identity theft. To protect yourself from identity theft, always shred anything with your social security number on it and don't give anyone your social security number unless you absolutely have to. Never keep your social security card in your wallet and always shred any credit card offers that you get, but don't accept.