Fill the field of the newsletter block, found by its label.
Examples
When I fill in the newsletter form field "Email Address" with "subscriber@example.com"
When we fill in the newsletter form field "Email Address" with "info@webship.co"
And I fill in the newsletter form field "Email" with "not-an-address"
When fill in the newsletter form field "Email Address" with ""
And we fill in the newsletter form field "Name" with "Jane"
Pattern
When(/^(I |we )*fill in the newsletter form field "([^"]*)" with "([^"]*)"$/, …)
Part of @webship-js/squarespace-steps (github.com/webship/squarespace-steps), a step pack for Webship-js 2.0.x.