The best email client on Android is a universal email app called Thunderbird. This free and open source app is built by Mozilla, the company behind the popular Firefox web browser. It's packed with features and add-ons, and it's also extremely customizable. Thunderbird is a powerful mail tool, featuring tab system, built-in web search bar, smart folders, and real-time contact chat. There are also two different modes of display: landscape and portrait.

Despite being a universal email app, it does support all of the major email services. Its design is incredibly sleek and intuitive, and its action is lightning fast. Advanced security measures are built-in, and it's compatible with the majority of email providers. And the best part is that you can manage your emails with ease and security. It even supports multiple email accounts, and you can customize push notifications to each of them. There are plenty of other features, too.

Besides being able to handle multiple accounts, Universal Email App also has a number of other features that make it a great choice for your email. It has an advanced inbox system, which helps you manage many accounts at once. Unlike other email clients, you can even customize the UI and create smart clusters. If you're a heavy email user, you'll love how Spike organizes your emails. It's easy to use and offers hundreds of customization options.