Embedding WordPress iFrame is easier than you imagine. Active 2 years, 1 month ago. ... May this not work in a custom theme, then you want to look at how the content of the post is being processes. Ask Question Asked 2 years, 8 months ago. Does anyone know how to correctly embed their forms? Shortcodes can embed files or create objects that would normally require lots of complicated, ugly code in just one line. The traditional way to do it is by using the HTML attributes