Follow the appropriate instructions below to get your DNS zone files.
Some registrar services provide a method to download or export your DNS zone file.
Instructions for GoDaddy
Instructions for 1and1
Instructions for Google
Instructions for MediaTemple
Instructions for Names.com
Some domain registrars do not offer a straightforward option of exporting or downloading a DNS Zone file but it is possible through your cpanel.
Bluehost
Domain.com
HostGator
Here are generic instructions for how to get your zone file on registrars that require you to use a cpanel system to manage your domain.
Finally, with some registrars you can request an export of your DNS zone records from their Technical Support and hope they are willing to respond to your request. Known domain registrars requiring such a request include:
SiteGround
Enom
Domain.com