Magazine publisher Time Inc. has launched a new website called Motto aimed at younger women looking for advice about life, work and play.

Overseen by the editors who produce Time magazine and Time.com, the new website site will include contributions by celebrities and politicians, plus original reporting from Time magazine staffers. To help contain costs, Time Inc.’s Real Simple, Southern Living and Health will also provide articles.

The debut is the company’s latest stab at ramping up its digital advertising reach at a time when print ad revenue is declining. Time Inc.’s print and other advertising revenue fell 12% to $319 million for third quarter ended Sept. 30. While digital advertising revenue increased 22% to $79 million, it wasn’t enough to offset the decline in print.

“Historically we’ve been about what to know. Increasingly, readers are looking to us for insight on what to do,” said Edward Felsenthal, managing editor of Time Digital, which includes Time.com, apps and distributed content on other digital platforms. “We cover world events, but an enormous amount of our traffic, especially in social media, is about self-improvement and living a better life.”

Stories on the new site include “The World I Want My Daughters to Grow Up In,” by President Barack Obama, and “Ivanka Trump’s 9 Rules for How to Negotiate—and Win.” There are also videos on such topics as “6 Ways to Make Your LinkedIn Profile Stand Out.”

The company said more than half of Motto’s readers are expected to visit via their mobile phones and tablets.

Many of Motto’s stories will also eventually be available on Facebook’s Instant Articles platform, said Mr. Felsenthal, while some videos will be posted to YouTube.

Callie Schweitzer has been named editorial director of the website, which has two full-time staffers. “It’s intended to be inspirational and motivational,” said Ms. Schweitzer, who is also editorial director, audience strategy for Time Inc. The new website plans to post a dozen new stories daily plus two new videos.

Advertisers for its launch on Wednesday included Berkshire Hathaway Inc.’s Geico insurance unit. Meredith Long, publisher of Time magazine and its related digital properties, said Motto’s audience will appeal to marketers ranging from technology to automotive to finance, plus beauty and consumer packaged goods companies.

Motto is part of a string of investments Time Inc. has made in recent months to cater to younger women. In October, the magazine publisher bought HelloGiggles.com, a pop culture, beauty and lifestyle website. One person familiar with terms estimated the purchase price was in the range of $20 million. The same month, Time Inc. also purchased two websites aimed at younger women—xoJane.com and xoVain.com—for an undisclosed sum from Say Media Inc.

Reaching younger readers online has been a popular initiative for big magazine companies. Condé Nast, a unit of closely held Advance Publications Inc., in October purchased Pitchfork Media Inc. in a bid to boost its access to young men. And in November, Hearst Magazines, a unit of Hearst Corp., teamed up with Snapchat to launch Sweet, a lifestyle channel aimed at millennials on Snapchat’s Discover platform.

Write to Jeffrey A. Trachtenberg at jeffrey.trachtenberg@wsj.com