If you are diligent and patient, then you may not need any specific training to become a general transcriptionist.
You can self-train by purchasing transcription equipment and practicing transcribing different voice recordings. You will need someone else to judge your work.
There are several free online websites that helps people learn how to type fast and accurately. Many transcription companies either have their own training program, or will pay for the training of transcriptionists.
The best option is to take lessons and get certified. If you have never transcribed before, or if your work was rejected by any professional transcription company when you took their test, then you probably require training.
Get complete online training to become a successful work from home general transcriptionist, for a modest fee, at www.transcriptioncertificationinstitute.org. Become an intern after certification to build credibility and gain access to the transcription industry.