This is the best link from the actual MX gov! And my chrome work fine as long as I display it in Spanish. If it auto-translates, it screws the date up.It's been a long time since I have been handed a customs form on a flight from DFW. May be the luck of the draw but for the last year the forms were handed in the terminal.
I usually use the online customs site and print out the document (remember to sign it to make it valid) Datos de identificación
Select Cancun as the city and Cozumel as the terminal. Cozumel customs is under the Cancun office. The site does not like Chrome, use Edge or the iOS browser
And randomly sign your name on the front of it somewhere.