A certificate of accuracy is one way of using your CT seal.
ATA provides sample certificates of accuracy that you can modify for your own use.
Short-form certificate of accuracy
The sample short-form certificate of accuracy is designed for a document that does not require notarization. Its purpose is to declare a translator's qualifications in general terms. The certificate also identifies the translated document by title, reference numbers, and/or other unique identifiers included with the source text.
Long-form certificate of accuracy
The sample long-form certificate of accuracy is designed specifically, but not exclusively, for a statement being sworn before a notary. Its purpose is to declare a translator's qualifications and expertise in exact terms. It identifies the document by title, reference number, and/or other unique identifiers noted in the original.
This form would generally be used for documents submitted to courts, government agencies, credentialing boards, and administrative offices; however, it might also be modified for use when notarization is not required but the shorter certificate of accuracy is too general.
Additional Guidelines
To prevent your certificate of accuracy from being fraudently attached to another document, the title and reference numbers or other unique identifiers should be specified, and the certificate should be firmly attached to your translation of the original document.
If the original document does not have specific identifiers, it is recommended that your certificate of accuracy be included as part of your actual translation in order to make it impossible for the certificate to be detached and used elsewhere.