When you create shares for a company, you have the ability to denote whether a share is to be signed normally or under seal. This includes printing specific text on to the generated share certificate as a result of the issue.
This option is found on the share issue screen of enSecretary and the text which it contains is configured within this maintenance option. Because this option is a single tick box character there is no way to remove it entirely.
Please see Share Issue Option for how this option affects shares.