When adding a new Additional Insured, you have the option to include a Description of Operations and a Certificate Holder. If you specify a “Certificate Holder,” it will appear on your ACORD 25 certificate in the “Certificate Holder” box in the lower left. If you specify content for the “Description of Operations,” it will appear in the “Description of Operations” box on your certificate.
If you have already created the certificate, you won't be able to modify it. Instead, add a new Additional Insured with the corrected information and you will receive a new certificate. It is okay if it is the same as the existing Additional Insured.
If you would like to edit the information on your own certificate, see instructions here.