Task visibility in Todo is largely determined by the project to which the task belongs to, with some exceptions to keep in mind.

• If you can access a channel to which the task belongs to through a project, you can see this task - this means tasks in public channels can be accessed by everybody in the workspace,
• Assignees can see all the tasks they are assigned to, regardless of the project,
• Task creators can see all the tasks they’ve created,
• Task watchers can see all the tasks they’re watching.

Who can edit tasks?

Everybody in your workspace who can see a task, can also edit it.

See: How to create private tasks? See: Projects