If integration with your preferred Email Service Provider is not available in the corresponding menu, you can always integrate it via Custom HTML Form.
We have used Mailchimp as an example, click here to open this GIF in a new tab and view it in better resolution.
Here are the steps:
In you Email Service Provider, go to the desired list/audience and then create a form to collect emails for that list/audience. Then retrieve the HTML for that form
In Spotlightr, go to Integrations & APIs from the Settings menu.
Select Custom HTML Form
Name it descriptively and paste the code into the appropriate field
Click on the CREATE INTEGRATION button