Before you can add your DigitalOcean credentials to Portainer, you will need to create an API token in your DigitalOcean account.
Log into the DigitalOcean dashboard and select API at the bottom left. Click Generate New Token, enter a token name and an expiration time, and ensure that both Read and Write scopes are ticked.
To add credentials for a DigitalOcean account, from the Shared credentials page click Add credentials, then select the DigitalOcean option. Give your credential set a name and paste your API key into the box.
When you're ready, click Add credentials. Your credentials will now be available to you when provisioning a Kubernetes cluster on DigitalOcean.