COFETEL type approval certificate is mandatory before selling YOUR products in mexico.
Only Mexican companies may receive COFETEL type approvals or electric safety NOM certificates.
The Mexican electric safety NOM certificate is the only legal document accepted in Mexico.

Product Labeling:

In the last page of every COFETEL Certificate there are some guidelines that must be followed in order to keep your certificate as valid. If the guidelines are not followed your certificate may get cancelled.

The third guideline says that every certified product must have the certificate number, together with the trademark and model name printed on a label and the label must be affixed to the product in a visible place.

So as soon as you receive a COFETEL certificate for your product you must print labels with the certificate number, brand and model name of your product and paste the labels on each and every product that will be shipped to Mexico.

If you get an electric safety NOM certificate for your product you must make labels with the NOM marking logo and paste them on the product, so that customs authorities know that your product has already been tested and certified on safety NOM regulation.