An advertorial is part advertisement and part editorial. While it is admittedly biased in that it promotes a single advertiser’s product, service or point of view, it has more credibility with the readership than an advertisement and less objectivity than an editorial.
Most companies hire a professional writer to write the advertorial, then pay advertising rates to have it printed in magazines and newspapers. Sometimes graphic design companies are hired for layout. I can help with both professional writing and graphic design services.