Log in to MetaMask -> Click the Network drop-down -> Select Custom RPC
Network Name: Avalanche Network
New RPC URL: https://api.avax.network/ext/bc/C/rpc
Send AVAX to Your MetaMask Connected to Avalanche
Go to https://wallet.avax.network/, and access your Avalanche Wallet.
On the left, there is a list of options. Click "Cross-Chain"
3. Choose the "C Chain (Contract)" as the destination chain
4. Enter the amount you would like to transfer, and then click confirm
Now you can send the AVAX from your Avalanche wallet to your MetaMask wallet.
5. Select "Send"
6. Select "C Contract" as the Source Chain
7. Enter your MetaMask wallet address by copying and pasting it into the "To Address" field on your Avalanche wallet.
8. Confirm, and finalize the transaction.
Congratulations! You now have AVAX on your MetaMask wallet and can start using Avalanche with MetaMask.