A: Formly connects directly with Google Sheets so you can connect with Google Sheets first.
Then you can connect your integrated Google Sheets with 3000+ applications (including MailerLite, HubSpot, ActiveCampaign, Webhook etc) using Zapier, Pabbly, Make etc.

https://help.getformly.com/en/articles/9197053-connect-with-google-sheets-and-3000-applications

https://zapier.com/apps/google-sheets/integrations/mailerlite
https://www.make.com/en/integrations/google-sheets/mailerlite2

Direct integration with MailerLite will be available in the future (dates to be confirmed).