Embargoed release means that the press release is distributed to the journalists and they are asked not to publish or report the content before a certain date and time.
You can set the embargo date in the third stage of creating a press release. Choose the delivery date and time as usual. Then tick on Embargo and choose the date and time when the content is free to be published. Embargoed press releases will be published on LianaPress site on the Embargo date and time.
Please keep in mind that news embargo is not based on formal legislation. It is an established practice between the media and the spokesmen that has evolved over time.