Yes, you can use the free sandbox account provided by 360dialog for testing purposes. Keep in mind that this account has limitations and certain features, like media attachments, might not work. More details can be found at https://docs.360dialog.com/whatsapp-api/whatsapp-api/sandbox.
After completing the synchronization process in Chat.RPAiX, you should start receiving WhatsApp messages sent to your number. You can conveniently reply to these messages from within Chat.RPAiX.
In Chat.RPAiX, go to Settings > WhatsApp > 360dialog settings and find the option “Synchronize now.” Click on it to initiate the synchronization process.
After logging into your 360Dialog dashboard, navigate to Left menu > WhatsApp Accounts and generate an API key. Copy this key and paste it into Chat.RPAiX > Settings > WhatsApp > 360dialog settings.
Start by creating a new account at https://www.360dialog.com/.