Sometimes you need to apply an action to a group of tasks (or all tasks). Here is how to do this in Bitrix24:
Select tasks by ticking them in the list. Remember, you can use search & filters above task list.
Scroll down to the group action tab. Click Select Action to see the list of available actions.
Select the action you need, specify the additional parameters and click Apply.
This means you don't need to open each task individually, but you can apply the selected action to the group of tasks.
To apply an action to all tasks selected by the filter, including tasks on other pages, tick For all option.
In this case, the action will be applied to all the selected tasks, including their subtasks.