This is a very formal phrase that you use when making announcements to large groups. You can use this in writing, or when speaking on stage in front of an audience. You can imagine the president of a country using this phrase when giving a speech: My fellow Americans, I'm pleased to announce that today, due to our efforts, a nuclear showdown has been averted with North Korea. This phrase is used in business settings for formal announcements that are sent out to the company about new employees, promotions, good quarterly results, awards, and so on.