the short answer
A personal training contract template should define scope, term, payment and billing, cancellation and refunds, late payment, liability and assumption of risk, medical-scope limits, confidentiality and data handling, intellectual property, and termination. Online coaches need a few extra clauses for remote work - no in-person supervision, communication and response-time expectations, recording consent, time zone, and pause or freeze rules. The contract goes out first in onboarding, the client e-signs it, and you store a dated copy both sides keep.
This article is general information for coaches, not legal advice. Contract law varies by country and state, and a template is a starting point, not a substitute for an attorney who can review your agreement for your situation.