An account is yours. Do not share a sign-in in a way that lets someone else change the studio.
The voice is not a person. Do not present it as one. You do not record your own voice here.
Characters are added only after bKash confirms the payment this server started. A listed price can change before you pay. Bought characters stay until a voiceover uses them. Crop, reverb, delay, a filter, and video do not spend characters. The service can change or stop.
Nothing is charged automatically. Each payment is a checkout you start.
Sign-in through Gmail or Apple follows those companies' own terms as well as these.