app/views/devise/passwords/edit.html.erb
<h2>Change your password</h2>
<%= simple_form_for(resource, as: resource_name, url: password_path(resource_name), html: {method: :put, id: 'edit_password'}) do |f| %>
<%= devise_error_messages! %>
<%= f.input :reset_password_token, as: :hidden %>
<%= f.input :password %>
<%= f.button :submit, 'Change my password' %>
<% end %>
<%= render 'devise/shared/links' %>