20 CFR §702.203

1. (a)The employer must file its report of injury with the district director.
2. (b)If the employer sends its report of injury by U.S. postal mail or commercial delivery service, the report will be considered filed on the date that the employer mails the document or gives it to the commercial delivery service. If the employer sends its report of injury by a permissible electronic method, the report will be considered filed on the date that the employer completes all steps necessary for the transmission.