app/views/users/registrations/success.html.erb
<% provide :title, t("devise_views.users.registrations.success.title") %>
<h2><%= t("devise_views.users.registrations.success.title") %></h2>
<p><%= sanitize(t("devise_views.users.registrations.success.thank_you")) %></p>
<p><%= sanitize(t("devise_views.users.registrations.success.instructions_1")) %></p>
<p><%= t("devise_views.users.registrations.success.instructions_2") %></p>
<p>
<%= link_to t("devise_views.users.registrations.success.back_to_index"),
root_path,
class: "button margin-top expanded" %>
</p>