Add basic documentation for viewing a task

doc/topics/plan_and_track.md

@@ -31,6 +31,7 @@ Get work done as a team.
 - [Labels](../user/project/labels.md)
 - [Milestones](../user/project/milestones/index.md)
 - [Requirements](../user/project/requirements/index.md)
+- [Tasks](../user/tasks.md)
 - [Time tracking](../user/project/time_tracking.md)
 - [Wikis](../user/project/wiki/index.md)
 

doc/user/project/issues/index.md

@@ -49,3 +49,4 @@ To learn how the GitLab Strategic Marketing department uses GitLab issues with [
 - [Issues API](../../../api/issues.md)
 - [Configure an external issue tracker](../../../integration/external-issue-tracker.md)
 - [Parts of an issue](issue_data_and_actions.md)
+- [Tasks](../../tasks.md)

doc/user/tasks.md

+---
+stage: Plan
+group: Project Management
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+---
+
+# Tasks **(FREE)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/334812) in GitLab 14.5 [with a flag](../administration/feature_flags.md) named `work_items`. Disabled by default.
+
+WARNING:
+Tasks are in **Alpha**. Current implementation does not have any API requests and works with mocked data.
+For the latest updates, check the [Tasks Roadmap](https://gitlab.com/groups/gitlab-org/-/epics/7103).
+
+FLAG:
+On self-managed GitLab, by default this feature is not available. To make it available,
+ask an administrator to [enable the featured flag](../administration/feature_flags.md) named `work_items`.
+The feature is not ready for production use.
+
+Use tasks to track steps needed for the [issue](project/issues/index.md) to be closed.
+
+When planning an issue, you need a way to capture and break down technical
+requirements or steps necessary to complete it. An issue with tasks is better defined,
+and so you can provide a more accurate issue weight and completion criteria.
+
+To see the roadmap for migrating issues and [epics](group/epics/index.md)
+to work items and adding custom work item types, visit
+[epic 6033](https://gitlab.com/groups/gitlab-org/-/epics/6033) or
+[Plan direction page](https://about.gitlab.com/direction/plan/).
+
+## View a task
+
+The only way to view a task is to open it with a deep link,
+for example: `/<group_name>/<project_name>/-/work_item/1`