A domain transfer changes the registrar responsible for the registration, but it does not automatically move website files or email. The most important preparation is documenting the current DNS records and confirming where authoritative DNS is hosted.
What to consider
Check domain-lock status, administrative contact details, transfer eligibility and the authorization code. Avoid making unnecessary DNS changes during the transfer unless you understand how the registrar and nameserver configuration interact.
After completion, verify nameservers, DNSSEC if used, renewal settings and contact information so the domain remains under controlled business ownership.