Under seal filing – is a procedure allowing sensitive or confidential information to be filed with a court without becoming a matter of public record. The court generally must give permission for the material to remain under seal.

Filing confidential documents “under seal”, separated from the public court, allows litigants to navigate the judicial system without compromising their confidentiality, at least until there is an affirmative decision by consent of the information's owner or by order of the court to publicize it.

When the document is filed "under seal", it should have a clear indication for the court clerk

Court clerk

A court clerk is an officer of the court whose responsibilities include maintaining the records of a court. Another duty is to administer oaths to witnesses, jurors, and grand jurors...

 to file it separately – most often by stamping words "Filed Under Seal" on the bottom of each page. Person making filing should also provide instructions to the court clerk

Court clerk

A court clerk is an officer of the court whose responsibilities include maintaining the records of a court. Another duty is to administer oaths to witnesses, jurors, and grand jurors...

 that the document needs to be filed "under seal". Courts often have specific requirements to these filing in their Local Rules.

Normally records should not be filed under seal without a court permission. However, FRCP

FRCP

FRCP may refer to:*Federal Rules of Civil Procedure* Fellow of the Royal College of Physicians...

5.2 allows a person making a redacted filing to also file an unredacted copy under seal.