Use 1-Click Child-Links Azure DevOps extension to create predefined list of tasks

Use this extension to quickly add the same number of tasks to your work item within Azure DevOps project. For instance, you have many PBIs and all of them have the same tasks like Development, Testing, Code review etc.
If you don't want to enter such tasks every time when you create a new PBI, you can use this extension.

To install this extension, follow the link - https://marketplace.visualstudio.com/items?itemName=ruifig.vsts-work-item-one-click-child-links

Click Get it free button.
Select Azure DevOps organization from the drop-down list.
Click Install button.
Wait until you receive "You are all set" message.

Open Azure DevOps site.
Go to Project Settings.
Expand Boards and choose Team configuration.
Then, choose Templates.
Build up your own template with the tasks that you will be adding by 1-Click Child-Links extension.

Go to any Product backlog item to which you want to add tasks.
Click ... actions icon to open the menu.
Select 1-Click Child-Links option.

All tasks created in the template will be added as Child links to the selected Product backlog item.