Bitcoin
Download wallet from https://blockstream.com/green/ and install it on your computer
Go to settings and enable test networks
Go to Bitcoin Testnet and click on "Create New Wallet"
Confirm the passphrase and PIN
2 bitcoin wallets will be created for different protocols (BIP49, BIP84). For testing you can use both of them
Select the wallet and copy it's address
Go to faucet services https://bitcoinfaucet.uo1.net/send.php or https://coinfaucet.eu/en/btc-testnet. Insert wallet address and click on "Send testnet bitcoins"
After a few minutes, the coins will be transfered to the test wallet
To send test coins to XAMAX, you should click on the "Send" button and specify the XAMAX wallet address