After creating a Presentation, navigate to your Share page and then select the Presentation you wish to email to friends.  This will launch the Presentation in the Editor.  Now tap the Actions Menu (three ellipses) in the top right corner of the screen.   

Click the Email button from the Actions Menu to launch the email form that is native to your device.  Once you start typing an email address, a list of possible choices will come up to choose from.  

Select the right email address for your contact, enter a Subject, Message and/or Notes and then click the blue up arrow to Send.  (All of these fields are optional).  Your document(s) will be attached to the email as a PDF file.