The foundation will replace their Sussex Royal brand, after the Queen reportedly ordered them to stop using the word "royal" once they stepped down as senior working royals.
Details about the project were first reported in the Daily Telegraph (UK), which obtained paperwork the couple filed in the US last month showing they were looking to create their own charity, volunteering service and wide-ranging website.
For now, the pair are focusing their attentions on the coronavirus crisis, they said.
"Like you, our focus is on supporting efforts to tackle the global Covid-19 pandemic but faced with this information coming to light, we felt compelled to share the story of how this came to be," they said in a statement.
Harry, 35 and Meghan, 38, also revealed that Arche, the Greek word in the organisation meaning sources of action, was also the inspiration behind their 10-month-old son's name, Archie Mountbatten-Windsor.
"We connected to this concept for the charitable organisation we hoped to build one day, and it became the inspiration for our son's name. To do something of meaning, to do something that matters," the statement said.
"Archewell is a name that combines an ancient word for strength and action, and another that evokes the deep resources we each must draw upon. We look forward to launching Archewell when the time is right."
Not everybody is looking forward to that time: British broadcaster Piers Morgan, a notorious critic of Meghan's, has blasted the couple for making the announcement in the midst of a pandemic.
"Total number of f***s the British public give about these two announcing their 'plans' from Hollywood right now: 0," he wrote on social media.
