How the activity should be launched with android:launchMode

Use Cases Launch Mode Multiple Instances? Comments
Normal launches for most activities standard Yes Default. The system always creates a new instance of the activity in the target task and routes the intent to it.
singleTop Conditionally If an instance of the activity already exists at the top of the target task, the system routes the intent to that instance through a call to its onNewIntent() method, rather than creating a new instance of the activity.
Specialized launches
(not recommended for general use)
singleTask No The system creates the activity at the root of a new task and routes the intent to it. However, if an instance of the activity already exists, the system routes the intent to existing instance through a call to its onNewIntent()method, rather than creating a new one.
singleInstance No Same as “singleTask", except that the system doesn’t launch any other activities into the task holding the instance. The activity is always the single and only member of its task.

References
https://developer.android.com/guide/topics/manifest/activity-element#lmode