Blockchain explorers are websites that allow everyone to see all the details of every transaction that goes into the blockchain. Think of them like public web directories for every single crypto transaction. Each blockchain usually has its own blockchain explorer -- like this one for Ethereum or this for Bitcoin. 

To see a transaction’s explorer info in Zengo, tap a transaction in the history tab, enter its transaction details screen, and tap the Status line.

If you want to use a blockchain explorer outside of Zengo, find the search box and enter the transaction tx identifier (aka the string of numbers and letters that identifies each transaction). Below you can see an example of an Ethereum transaction:

Below you can see an example of an Ethereum transaction: