The question comes up for me all the time. Oftentimes, people do not know if they need to show up for court or simply sign a written statement, called an Affidavit.
Here are the rules for an in-person hearing, usually called a trial or an evidentiary hearing: anyone who will be a witness, who will make a statement to the court has to be there in person to do it. If the hearing is by video, they would sign onto the hearing remotely using a computer. For trials and evidentiary hearings, a witness cannot send in a written statement, they have to be there.
For hearings that do not involve witnesses testifying, usually called motion hearings, sworn written statements called affidavits are signed by the witness and are submitted to the court. For these types of hearings witnesses do not speak in court, the judge makes decisions based on the written statements.
It is critical for anyone involved in a court case to know exactly what type of hearing they have, whether witnesses will speak at the hearing, or if they will submit written affidavits to the court. For hearings based on affidavits, there are deadlines for them to be filed with the court. Hearings with witnesses speaking in court usually have deadlines to file lists of who the witnesses will be.
If you do not follow the rules exactly, there is a good chance that you will not be able to have your witnesses file affidavits or speak in court. Whatever you do, make sure you know what type of hearing you have.
Ed