To accept payments, you need to setup your Stripe account. Please visit this link to signup/register with Stripe. Once you setup your Stripe account, you'll have to generate Stripe API Keys.
To generate the Stripe API Keys (Secret Key and Publishable Key) please follow the steps give below:
STEP 1: Log in to your Stripe dashboard.
STEP 2: Go to API keys in the left hand side menu.

STEP 3: Your secret and publishable keys should be visible on this page. Before using the generated secret keys, you will need to use the toggle switch that says “Viewing test data”. You have to set it to ”Viewing live data”.

STEP 4: Now click on Reveal live key token

Paste the Secret and Publishable Keys in "Business Tools" settings section as shown below:
