We are sorry for the delayed response, we offer free transfers between Dynadot accounts, here is the link to the help files on our site that can help you to initiate the transfer if you are the owner of the domain:
How do I initiate a change ownership request if I am the current owner (domain push)? https://www.dynadot.com/community/help/question/domain-push
If you want to move multiple domains at once, if you're the owner you can follow these steps here:
How can I do a bulk change ownership request? https://www.dynadot.com/community/help/question/bulk-change-ownership