A more thorough explanation:

A notice of appeal is a legal document that is filed with a court to let them know that someone intends to appeal a decision made by a lower court. This document is also served on the other parties involved in the case. In most cases, filing a notice of appeal is the first step in the appeals process.

For example, if someone is unhappy with the outcome of a trial court's decision, they can file a notice of appeal to have a higher court review the decision. This document must be filed within a certain timeframe after the trial court's decision is made.

Another example is in federal court, where the Federal Rules of Appellate Procedure require that an appeal is taken by filing a notice of appeal with the clerk of the district court. The clerk then sends copies of the notice to all the other parties' attorneys, as well as the court of appeals.

Overall, a notice of appeal is an important legal document that initiates the appeals process and allows someone to challenge a lower court's decision.