app/views/devise/invitations/edit.html.erb
<h2><%= t "devise.invitations.edit.header" %></h2>
<%= form_for(resource, as: resource_name, url: invitation_path(resource_name), html: { method: :put }) do |f| %>
<%= render "devise/shared/error_messages", resource: resource %>
<%= f.hidden_field :invitation_token, readonly: true %>
<% if f.object.class.require_password_on_accepting %>
<div class="field">
<%= f.label :password %><br />
<%= f.password_field :password %>
</div>
<div class="field">
<%= f.label :password_confirmation %><br />
<%= f.password_field :password_confirmation %>
</div>
<% end %>
<div class="actions">
<%= f.submit t("devise.invitations.edit.submit_button") %>
</div>
<% end %>