Colorado Certificate of Service is a document used to certify that a legal notice or other document has been served to its intended recipient. It is usually a form signed by the person who served the document and includes information such as the date and time of service, how the document was served, and the name and address of the person served. There are two types of Colorado Certificate of Service: Regular and Electronic. Regular Colorado Certificate of Service is used when documents are served in person or by mail, fax, or other non-electronic means. Electronic Colorado Certificate of Service is used when documents are served electronically, such as by email. Both types of Colorado Certificate of Service are used to prove that a legal notice or other document has been properly served and received.