The recipients of the composed message can be freely entered into the To or Cc fields in the header section of the compose screen. Separate multiple addresses with a coma (,). Make sure you enter full and valid email addresses.
Address Book Autocompletion
While typing a recipient address, the app continuously searched your address book and suggests matching entries right below the input field. Use the cursor keys (up/down) on the keyboard to select one and then hit <Enter> or <Tab> to copy the highlighted address into the recipient field.
Using the Address Book Widget
If you prefer to select recipients from a list of contacts, use the address book widget on the left side to look them up. First, select the address book to browse on the upper part of the widget and see the contacts listed below. Only a limited number of contacts is displayed at a time so use the arrow buttons in the widget header to jump to the next page of contacts.
Select one or more contacts in the list and then click either one of the buttons below (To+, Cc+, Bcc+) in order to copy the selected contacts to the according recipient field. Double-click a contact in the list to have it added to the To field immediately.