In addition to emailing x@mail.asana.com to create tasks in your default workspace, you can also create tasks in any Asana project. Here's how:
 

1. Find the ID number of the project 

   • Go to Asana and view any task in the project

   • Look at the URL, it should look like http://app.asana.com/#/0/FirstNumber/SecondNumber

   • The FirstNumber is the ID number of the project
      

2. Email or Forward an Email to x+FirstNumber@mail.asana.com.

   • For example, if FirstNumber is 123, you would email x+123@mail.asana.com

   • The email address you send from must the same one you have set in Asana
      

3. Create a contact in your email client so that you can auto-complete the email address without remembering it

   • In Gmail, you can do this by clicking on "Contacts" then "Add Contact" then set the name to the name of the project like "Assigned To Me - Work," and the email address to the x+FirstNumber@mail.asana.com

To assign a task to someone, put them as the only person in the To: field (you can add the asana email here or in CC/BCC)

To add someone as a follower, put them in the CC: field

Attachments to emails will survive and will attach to the task created. 

To complete a task, reply "Complete" as the first line of your reply to an email notification for a single task update