Right now it is available to purchase only ETH and USDT in the 3Commas wallet using your bank card and here is how you can do this.
Open the 3Commas wallet app
Tap on the Wallet button
Tap on Buy button
Choose the assets you want to purchase
Or you can choose the coin from the list, tap on it and tap on Buy button:
Enter the amount of funds you want to spend, choose the currency, and tap on Buy *Coin* button (Buy Ethereum on screenshot)
Verify the information and tap on Buy button
If you are not logged in or registered yet, you will need to accept the Terms of Service and verify that you are older than 18. Then it will require to enter the email (or phone number) and confirm it with the code.