The Microsoft Windows 8 and 8.1 "Startup folder" is in the same location as it was in Windows 7 and Windows Vista.
The location is: %AppData%\Microsoft\Windows\Start Menu\Programs
Using Windows Explorer, put that path into the location bar:
Press enter and look for the Startup folder:
If you desire, you may create a shortcut by right-clicking the Startup folder and choosing Pin.
Now that you know how to find the Startup folder, let's make something startup!
Suppose you find it useful to start the Task Manger when you log on. Let's place the Task Manager in the Startup folder.
1) Open the Startup folder with the foregoing instructions.
2) Find a shortcut to Task Manager by starting a search for "task manager". Open the folder containing the Task Manager.
3) Copy the Task Manager shortcut (right-click on Task Manager, copy) and paste it into the Startup folder (in Startup folder, right-click, paste).
The Startup folder will now contain the Task Manager shortcut:
The next time you log in to your account, the Task Manager should automatically start. Programs such as Microsoft's Paint will easily start, while Task Manager may require a tweak. If Task Manager is not starting, try to make a change to user account settings:
Control Panel > User Accounts and Family Safety > User Accounts > Change User Account Control Settings > Never Notify. Frankly, I don't recommend making this change, so this hasn't been useful for automatically starting Task Manager.