Amazon has announced on Friday, July 1, that its voice assistant Alexa now understands user's brand preferences and allows ordering tens of millions of products by using voice commands.

According to The Wall Street Journal, Amazon.com Inc. has improved the shopping capabilities of its voice-controlled digital assistant. Alexa, a voice command based bot, is now able to help its users purchase "tens of millions" of products from Amazon's massive online store.

VentureBeat reports that Amazon's Alexa virtual assistant is integrated in devices like the Amazon Fire TV, Amazon Tap, Echo and Echo Dot. Alexa users can now tell the bot through any of these devices to order Amazon products.

Up to date, Alexa was only able to order the Echo Dot, Amazon's Choice products or to reorder previously ordered items. Now, Alexa can order tens of millions products from Amazon, but the product ordering capability is limited to Amazon Prime customers.

According to Amazon, the personal assistant cannot order Add-On items, Prime Now, Prime Pantry, Amazon Fresh, jewelry, shoes, apparel or watches. There are still some limitations mostly around things that require sizing like shows and clothes, but Amazon is planning to add new products over time.

Since it has been launched on the market two years ago, Alexa's rollout has been gradual. However, it seems lately that the virtual assistant has become important for the future of Amazon. Just weeks ago, the CEO of the major online retailer, Jeff Bezos, said that Amazon Echo could turn out to become the fourth pillar of the company, its retail marketplace, Amazon Web Services and Amazon Prime.

Alexa's new purchasing option has been rolled out just days after Amazon Tap and Amazon Echo users learned they can add more than 1,400 skills. Alexa Skills Kit (ASK) was launched by Amazon for developers one year ago.

In March, CapitalOne has been added to Alexa, as well. Fortune reports that Citibank account holders may soon be able to pay bills with Alexa.