I would like to send a single task (and not a group of tasks/a project) to another people via email.
If you want to send a task from your to-do list in Todoist to someone else, then unfortunately, that's not possible right now.
However, if you'd like to send a task to someone else's Todoist task list then you can do to using the "Send task via email" feature. To find detailed information about this feature, please right-click on a project and choose "Email tasks to this project" from the context menu.
Here, you will find the unique email address of this particular project and, at the bottom of this window, an option to add other email addresses which will be authorized to send tasks to this project. To send a task to someone else, you need to know the ID of their project and your email address must be added on their list of accepted addresses.
Furthermore, if you're working in a team and you'd like to assign tasks to people more ofter, share updates or files, we recommend our team-based project management tool https://wedoist.com
We get the feeling that Wedoist is nowadays a dead product and all development is put into Todoist. From that point of view, what about the subject of this thread?
Can you send a mail in Todoist to a colleague, it becomes a task AND you can read the body of the mail (not only the subject)? If so, how...?
Yes, you can do this. Right-click on a project and choose "Email tasks to this project". You'll find all the information about this feature there along with the unique email address of this project :-)