Francesca,
Mexican citizens do not require a visa to visit the Schengen Area (including Switzerland) provided that:
1) The visit is for tourist purposes only (no working)
2) the stay is limited to 90 days in any 180.
3) Their passport is valid for 3 months after they leave the Schengen Area.
- The "Documents" the websites refer to are your passports.
- The fact you are travelling from the USA is irrelevant, it is your citizenship which matters.
If you don't believe me, here are the regulations on the EU website: https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32018R1806&from=EN
Scroll down to "ANNEX II
LIST OF THIRD COUNTRIES WHOSE NATIONALS ARE EXEMPT FROM THE REQUIREMENT TO BE IN POSSESSION OF A VISA . . "
And you see Mexico is in the list.
And the same thing in Spanish (the EU publishes all laws in all EU languages) https://eur-lex.europa.eu/legal-content/ES/TXT/HTML/?uri=CELEX:32018R1806&from=EN
Wikipedia page with all the rules: https://en.wikipedia.org/wiki/Visa_policy_of_the_Schengen_Area