It is a more formal way of saying “a period of time that is famous for something (an idea, a type of economy, a trend, etc.)

In European history, we can talk about “the Napoleonic Era”, the time when Napoleon was in power in France and in Europe. In US history, there was the “Era of Good Feelings”, a time of national unity from the 1810s to the 1820s.

“The end of an era” is something you can hear media people say when someone very famous dies.

It depends of the context...

Example

Verb

He was the best:

Él era el mejor

Welcome to the new era

Bienvenido a la nueva era

This is very helpful , thanks :)