Apple Looks to Expand Advertising Business With New Network for Apps

Increasing ad sales could help offset slowing iPhone growth, but effort would face stiff competition from Google and Facebook

Apple Inc. prides itself on selling devices rather than relying on ads.

Now the iPhone maker is looking to expand its digital-advertising business, people familiar with the matter said, as it shifts its growth strategy beyond selling devices toward pushing services on them.

Over the past year, Apple has met with Snap Inc., Pinterest Inc. and...