leadchat/app/views/mailers/conversation_reply_mailer/email_reply.html.erb

<% if @message.content %>
  <%= CommonMarker.render_html(@message.content).html_safe %>
<% end %>
<% if @message.attachments %>
  <% @message.attachments.each do |attachment| %>
    attachment [<a href="<%= attachment.file_url %>" _target="blank">click here to view</a>]
  <% end %>
<% end %>