How can I try to use Lightning Network on bitcoin testnet?
You can use
Eclair Mobile Testnet. You need to use some faucet to obtain testnet coins and then you can open a channel with some node.
and What is application app for use Lightning Network both on testnet and on bitcoin Lightning Network real live?
I can't recall an app like that. If you want to use the wallet above on mainnet, you need to download
the mainnet version. There are also a few other mainnet wallets that you should consider:
Phoenix Wallet,
Breez Wallet,
BlueWallet (custodial Lightning wallet; you don't have to open channels on your own channels).