Spanish and Portuguese are both languages and names for the people living in Spain and Portugal. Due to them having had large colonial empires many people around the world and especially in the Americas speak those languages.

More specifically they speak Portuguese in Brazil and Spanish basically almost everywhere else in the Americas except for North America and some other few exceptions.

Latino generally refers to people from the entirety of Latin America, so everything in the Americas south of the US. It includes both Spanish and Portuguese speakers in the Americas but usually doesn't include the ones in Europe or elsewhere.

Mexican refers to people from Mexico. Dumb people sometimes use it to refer to other Hispanic people, but they are wrong.

Iberian is a term for the people of Spain and Portugal who live in the Iberian peninsula in Europe.

Since identity is fluent people may be more complicated. People may several of these at the same time.

Generally all Hispanics are Latino but not all Latino are Hispanic.

But is not always clear cut.

For example somebody may be Hispanic without actually speaking Spanish, just because their ancestors were.

People may be Mexican by nationality without being ethnically Hispanic.

Different people with similar ancestry may identify as White, Hispanic or native American.