Top-up your account by card
It is important to point out that having a positive balance (also known as credit, funds, etc) is necessary to be able to send messages. Here you can check how the SMS service is charged.
In summary, even if you are using the free plan, every sent message incurs a cost.
You can top up your account by following these steps:
1. Click on Billing settings
2. Select the amount
3. Fill your billing information.
4. Select credit card payment
Provide the card number, as well as specify if you want to save the card for future payments. The payment will be processed through a Payment Gateway (managed by Stripe).
5. Complete the payment
After completing the payment, your corresponding balance will be enabled, and an invoice will be generated for you to download
You might be interested in learning how to top your account using PayPal
You might be interested in learning how to top your account via Wire Transfer