Almost one million companies in the UK and around the world can now create a single online store to sell products, for free, on Facebook and Instagram.
The initial phase of the launch of Facebook Shops has been brought forward and extended due to Covid-19.
The stores will appear on company pages, Instagram profiles and through targeted ads.
The company has already used a free approach in its Facebook marketplace for personal ads.
"It's bigger than usual just because we want to make sure we're moving quickly to put these tools in the hands of as many companies wherever they are, large or small, to help them survive during this time," said Layla Amjadi of Facebook.
And product manager George Lee said it had been in the pipeline for at least six months.
"Obviously, given the current situation, we have accelerated many of our efforts," he said.
"We are in a unique position to be able to contribute to the survival of a group of these companies."
The purchase function will also appear on WhatsApp and the other messaging apps of the company and will integrate with live streams.
For the average Facebook user, "it will be a seamless experience," said Amjadi.
"Now you can go much deeper without leaving the app."
Once a buyer decides to spend money, they will usually be directed to the company's website to complete the transaction.
And if problems arise or if a buyer wishes to ask questions, he can do so through Facebook Messenger, WhatsApp or Instagram Direct messages, some of which are already used by companies for this purpose.
The implementation is part of a wider range of planned changes for shopping across Facebook products, including:
- a loyalty program that will connect things like points from local bars to Facebook
- a Shop button, where products and brands will be shown, on the main Instagram navigation bar
Anthony Ha, a senior writer on the TechCrunch technology news site, said the blockade of the pandemic may have worked in Facebook's favor.
"After all, if your favorite shop changed the time or switched to online delivery or pickup on the sidewalk, they almost certainly posted a post on Facebook or Instagram," he said.
"So it makes sense for Facebook to make the buying process as simple as possible from those profiles.
"From a business perspective, the obvious goal is to promote more advertising.
"But it's also worth mentioning that the economic fallout from the pandemic is likely to kill many small businesses, including those who publish and advertise on Facebook.
"So the company has a stake in helping those companies survive in any way they can."