Yes, Freewallet Lite is an HD (or "hierarchical deterministic") wallet. That means a new address will be generated every time you send or receive funds, which makes your transactions harder to track.
There’s no need to backup each address separately, all of them can always be restored with your wallet’s 12-word mnemonic phrase.
All addresses generated from the same wallet can be used to receive funds, and all funds sent to any of these addresses will show up in your balance. The balance you see on your main wallet screen represents the total sum among those addresses.