Texas auto · The territory is on the policy
The Texas Department of Insurance says most auto policies do not cover an accident while you are driving in Mexico. The same table says most policies do cover other states and Canada. Read yours. This page will not quote a Mexican liability minimum.
TDI’s auto guide puts Mexico in the column of what most policies do not cover, in the same cell as driving for a business and racing. It also says coverages vary and that you should read the policy. If the territory stops at the border, a crash in Mexico is not a claim on that contract. Your Texas liability floor, $30,000 per person, $60,000 per accident, and $25,000 property damage, is a Texas requirement. It does not travel into a country the form excludes. A policy that says it covers driving in Mexico is a different contract. It is not created by showing a Texas card. This page will not invent what Mexican authorities require you to carry.
En español: el mismo punto. What the Texas policy is: what it covers, car insurance in Texas, and liability versus full coverage. Los tipos, en español: coberturas de auto.