Facebook's chat service WhatsApp is adding more ways for companies to communicate with customers, and opening up a new way for the parent company to cash in.

While WhatsApp doesn't have advertising outright, it is increasing functionality for businesses on its platform called WhatsApp Business. An update Wednesday to WhatsApp Business will allow companies to send information to customers through the app. Companies can also add a link to their WhatsApp chat on their website or pay Facebook to promote the chats in an ad.

Companies can use the WhatsApp chat feature for free, as long as they respond to a customer's message within 24 hours. Otherwise, the company has to pay a fee to WhatsApp. It charges a fixed rate per country, ranging from about half a cent to 9 cents per message, according to a WhatsApp spokesperson.

Facebook's move is its latest attempt to monetize the other apps in its portfolio, like WhatsApp, Messenger and Instagram. Facebook said last week that 2.5 billion people use its family of apps each month.

During a call with analysts for its second-quarter earnings report, Facebook projected lower revenue growth and operating margin growth.

But it still could have room to grow with its other apps, including WhatsApp. Allowing people to click a Facebook ad to get to a WhatsApp Business chat could encourage more businesses to buy more advertising. Charging for customer service messages may provide an additional revenue stream. The company has also added similar customer service and other ad opportunities on Messenger to attract businesses.