tinymce-docs-4x/_includes/configuration/element-format.md

element_format

This option controls whether elements are output in the HTML or XHTML mode. xhtml is the default state for this option. This means that for example <br /> will be <br> if you set this option to html.

Type: String

Default Value: xhtml

Possible Values: xhtml, html

Example:

// Output elements in HTML style
tinymce.init({
  selector: "textarea",  // change this value according to your html
  element_format : "html"
});