You can choose to convert any inbound email to a new task for a client.
Doing this will quickly create a task with the exact body of the email in the description of the task. You can then edit this description, along with the title of the task, start and due dates and assignment.
1) Open the email tab on the client's record
2) Choose the email you wish to convert to a task
3) Click on 'Convert to Task' at the top of the email
4) Use the task creation window to set up the task the way you want. When you're happy, click confirm.
You will then be able to view the task on the Work tab of the client's record.