Creating a Mercadopago Account :
 

Step 1. To create an account or log in to the official Mercadopago. please visit https://www.mercadopago.com.br/

Step 2. The private key for the application will always be utilized in the backend to create payments, and that key is known as an access token. They can be found on the Dashboard or in your Mercado Pago account by accessing Your Business > Settings > Management and Administration > Credentials.
 

https://www.mercadopago.com.br/developers/en/docs/credentials

Step 3.  Login to your Foodomaa Admin Dashboard

Step 4. Go to Settings > Payment Gateways > Mercadopago, and paste the access token that you got from Step 2.
 

Step 5. Save the settings.