This command starts the quest with the specified ID. Note that you need to surround the quest ID in single and double quotes like so - '"Quest ID"'.
The syntax for the startquest command is as follows:
/startquest ["quest id"'] Debug Mode
This command has the following arguments:
|"Quest ID"'||The ID of the quest you wish to start, surrounded by single and double quotes ('" and "').|
Find below working examples of the startquest command.
The above command would start the protectorate quest.
The above command would start the first Apex Mission quest.