To change the title, go to Settings -> Advanced and in the Page title, set tags.
You can use the following tags:
{{account_name}} - displays the account name
{{counter}} - Displays the number of unread messages in the inbox
{{title}} - displays the title of the page on which it is currently located (eg "Clients" or the title of the email if we are reading the e-mail)
An example of a title display where the {{title}} tag is at the beginning:
