CM User Submitted Posts - Form Display
To display form, place shortcodeon post/page.
Embedding Images and Media
By default only Administrators, Authors and Editors roles can use the "Add media" option since those roles have the "upload_files" capability and are allowed to use the Wordpress' Media browser.
If you want to allow a regular user to embed media (such as images, videos or other files) you have to give him the "upload_files" capability. However it's not supported by pure Wordpress and you have to use an external plugin such as User Role Editor. Install it and add the "upload_files" capability to a specific user or to the entire Subscriber role in order to allow all regular users to use the Media browser.