Select "My Domains" from the left-side menu bar and click "Folders" in the drop-down.
Your folders will be listed here which can be used for both the Dynadot domains and domains from Other registrars. If you do not have any domain folders set up, you will find 2 default folders with the names "(no folder)" and "All".
Click on the "Download" icon at the top right of the page
Choose the folder you want to download from the "Folder" dropdown. Select from the options provided to optimize your file and click the "Download" button on this page.
The list will be downloaded in a .CSV file format.