You have to have oral testimony by the plaintiff, in person, and in the courtroom, to obtain a divorce. Family Law Section 1-203 and Rule 9-209.
That testimony has to be corroborated by someone or something other than the parties to the divorce. Family Law Section 7-101(b). A marriage certificate can corroborate the marriage. A notarized written agreement signed before the complaint was filed can corroborate a mutual and voluntary separation. Family Law Section 1-104.
But most of your testimony is corroborated by a witness. That testimony also has to be oral and in court “unless otherwise ordered by the court for good cause”. Rule 9-209.
What is good cause? The court has allowed me to use telephone testimony in a handful of cases where the corroborating witness was a geographically distant relative or a busy mental health professional. In one uncontested divorce, I was permitted to corroborate adultery with the deposition transcript of the paramour, but the judge let me know he would have preferred live testimony. If you are going to try to corroborate without a witness in the courtroom, call the judge’s clerk or secretary before the trial to make sure it will be permitted.