The Certificate of Incorporation is issued to newly registered companies. This document confirms the company name, number and date of registration. The document will also show the country in which the company was registered as well as the law under which the company was formed.
If your company was formed within the last few years you may have received this document electronically. It is possible to obtain a formal replacement document that is printed on the standard Companies House card and signed by a Companies House registrar.
If you are not in a rush you may be interested in the standard service.