Facebook Inc. unveiled plans on Wednesday to beef up its Messenger mobile application to allow users to book reservations, track online orders and send custom videos, a push to make the app a tool for commerce.

The social-networking company also announced an embedded video player that will make it easier for users and publishers to host Facebook videos on their pages, and it launched a tool to help businesses track mobile ads’ effectiveness.

Facebook also simplified how users share content online and said it is joining with several publications, including BuzzFeed, to host reader comments on online articles.

The moves mark a deeper commitment by Facebook to develop and extend its suite of mobile apps, which include Instagram and WhatsApp, as well as Messenger.

“Moving from just being a single service to a family of world-class apps to help people share in different ways is the biggest shift in our strategy to connect people in many years,” Chief Executive Mark Zuckerberg told roughly 2,500 attendees at Facebook’s annual F8 developers’ conference in San Francisco.

Launched as a stand-alone app in 2011, Messenger now has 600 million users. WhatsApp, which Facebook bought a year ago for $19 billion, has 700 million users. Some 1.4 billion people visit Facebook at least once a month.

On Wednesday, Facebook said about 40 other apps now connect to Messenger through the Messenger Platform, including e-commerce companies Zulily Inc. and Everlane.

Executives laid out a vision in which consumers can shop online and buy items by sending a thumbs-up icon, a feature that could keep users in the app for longer periods. The initiative is led by David Marcus, who was hired from eBay Inc.’s PayPal unit last year to run Messenger.

Opening Messenger to businesses offers a communication tool between companies and customers to supplement email. But few big-name retailers have signed up and it is unclear how many consumers will sign up for the service, said Macquarie Securities analyst Ben Schachter. “This notion that you’re broadening out this platform—that’s what’s interesting, not specifically what they showed today,” Mr. Schachter said.