You may check if your domain is transferrable by going to:
and entering your domain name in the form (make sure to select the TLD -- .com, .net, or .org -- from the dropdown box insted of entering it in the textbox). If you are able to proceed with the transfer process, the domain is transferrable.
Otherwise, you will receive an error followed by a reason:
The domain your-domain.com is not currently transferrable: [reason]
One of the most common reasons:
Domain Status: clientTransferProhibited does not allow for transfer.
indicates that your domain is "locked". If you own the domain and you still want to transfer it, you will need to log in to your domain control panel and unlock the domain first. If you cannot find a way to unlock your domain in the control panel, you will need to contact your domain name host to unlock the domain for you.