Electronic Case Filing (ECF) is an computerized filing system, originally developed in Tarrant County, Texas. The original purpose was to enable law enforcement agencies such as police, district attorneys, criminal courts, etc., to process and exchange information quickly and efficiently. More recently, the filing system is now being used for the means that all court documents are submitted.
Whether or not attorneys file their pleadings via ECF depends on their jurisdictions. Further, not all jurisdictions will require that all forms of pleadings be filed electronically. While most states use ECF for bankruptcies, they don't use it for all filings. So, an attorney may file a bankruptcy pleading or documents using ECF for one client, but they may still have to visit the court clerk in order to file a divorce pleading for a different client.