The chatbot removes any need for people to leave the chat if they are looking for something such as an address or the name of a restaurant. Users can type "@google" and then their question while using the app, either one-to-one or in a group chat.
In a blog, Google said: "The Google Assistant is the next chapter in a journey Google has been on for many years to assist people in their everyday lives. We’re starting with a preview edition to show you just one way that your Assistant will work for you in chat.
"Over the coming months, your Assistant will be available in more Google products, working seamlessly throughout your day at home or on the go. The Assistant will initially be available in English, with more languages coming soon."
Allo also has a smart reply feature which suggests responses and gives people the option to reply with a tap if they are on the go. Google said that this will improve over time as the platform learns whether the person prefers to use emoticons or text.
There is also the option to make emojis and text larger or smaller, and scribble on photos before people send them.
Allo will be available over the next few days on Android and iOS.