In order to create a Liquid Testnet wallet, you will first need to enable Testnet in Blockstream Green's settings. Liquid Testnet wallets operate on a separate network than the Liquid blockchain, and are used solely for testing purposes. Testnet wallets allow developers or testers to experiment without having to risk actual funds. The funds in these wallets have no value.
Mobile
1.
Open Blockstream Green and select App Settings.
2.
Tap to Enable Testnet and Save your changes.
3.
Choose Add Wallet, agree to the Terms of Service, then tap New Wallet. When asked to choose your network, select Liquid Testnet.
4.
Record your recovery phrase and enter a PIN, then the setup of your Liquid Testnet wallet will be complete.
Tip: To begin experimenting on the Liquid Testnet, acquire some testnet L-BTC by visiting the link here.