Android Auto is a feature that helps you use your phone while still keeping the focus on the road. Once you connect Android Auto to your phone, the apps will be displayed on the screen. You can tap the screen to do things like send a text message, make a phone call or get directions. Google Assistant is a feature that you can use along with Android Auto to get extra assistance. You can use your voice to call someone, get directions and play music.
You use Google Assistant by simply saying "Hey Google." There are many navigation tools that are available via Waze or Google Maps. You can get traffic alerts and find points of interest. You can also share your estimated time of arrival with other people. Additionally, Google Assistant allows you to get text message read to you and reply to them with your voice.