Domain Authorization code (Auth code, EPP code) is a unique set of characters that is assigned by the registrar at the time the domain name is registered. It consists of at least 1 letter, 1 number, and 1 special symbol and can have from 8 to 32 characters total and it is used when you would like to transfer your domain from one registrar to another.EPP code is a special security feature that helps to ensure that only the domain owner can initiate the transfer of his domain and we would not recommend our customers providing it to anyone unless it's the registrar the domain is transferred to.
Some hosting company may ask you to provide the EPP code in order to verify the domain you host with them. Please note that there are alternative methods of verification like change of nameservers, etc. Generally, the hosting company should not require the EPP code; the only reason they need it is to transfer the domain to them. Moreover, it is also impossible for the hosting company to verify the EPP code without submitting a transfer request.