Hi bblendernoob ,
If your whole so-called Header is missing, something like in the following screenshot, click on the little down arrow on the top right:
If you unintentionally deactivated something you also can reset to the blender defaults with File > Defaults > Load Factory Settings.
Of course if you intentionally made changes to your Layout then those will be gone too.
As Martin wrote above, it is likely at some point this setting was deactivated 
In which case, you will indeed see this tiny downward facing arrow. clicking on it will reveal your header with all the menus.
If your menus are not showing, it is possible you've hidden them through some operation along the way also.
Those three little lines show that it is collapsed. 
To get them back, right-click on any button that is visible so you get this option in a dropdown:
And you can re-enable Show Menus.
