You can upload content to be sent by going to:
HTML, ZIP
Zip File imports simply the process of uploading a single HTML file and its accompanying images. Senders that work with designers are often provided with a Zip file containing the HTML file, and its accompanying images. When you upload a ZIP file to ReachMail, we automatically import the images for you and make the appropriate adjustments to the HTML to reference the image URLs not hosted in our networks.
Only local images (those contained in the ZIP file) are handled. Images reference in the HTML that is already hosted online will not be altered.
Please ensure that the ZIP archive contains only one HTML file.
Also, make sure your HTML is email specific. There is a great tool at caniemail.com to see if the HTML you are using is supported in email. This is great for those that have written your HTML code.