app/views/devise/confirmations/new.html.erb
<h2>Resend confirmation instructions</h2>
<%= form_for(resource, as: resource_name, url: confirmation_path(resource_name), html: { method: :post }) do |f| %>
<%= devise_error_messages! %>
<div class="field">
<%= f.label :email %><br />
<%= f.email_field :email, autofocus: true, autocomplete: "email", value: (resource.pending_reconfirmation? ? resource.unconfirmed_email : resource.email) %>
</div>
<div class="actions">
<%= f.submit "Resend confirmation instructions" %>
</div>
<% end %>
<%= render "devise/shared/links" %>