If you are trying to email tasks to a project (email to create a task) and you are not able to it. this is because you have to add that address to your accepted list of emails.
Head to Todoist.com, and right click on a Project which you'd like to email tasks to, click on the "Email tasks to this project" link.
On this page at the bottom you will have an area where you can enter email addresses which will be accepted. Add your work email to this. The address at the top is the one you will email to.
Thanks for the prompt reply, maybe I did not explain well what I want to do. I want to do is being on the Gmail inbox, select a message and add it as a task. Are currently only leaves the option to add website as a task.
Sorry for the misunderstanding.
For this to work, the email in Gmail must be opened. If you are just in the inbox, selected or not, nothing will happen.