You can simultaneously work with several accounts without entering your username and password every time.

To use this feature, go to your folder list by tapping the  “Menu” icon in the upper left corner of the screen. Touch the  "Plus" icon under your current mailbox's avatar.

On the page that opens,  tap the icon of your email provider, or tap “Other” if your email provider is not listed. Еnter the name of another one of your mailboxes (username), enter the corresponding password, and tap "Sign In". 

Now switching from one mailbox to the other is as simple as going to the folder list by tapping the   “Menu” icon and touching the image for the mailbox you want to use. The number of unread messages in the mailbox is displayed in the corner of the avatar.