How to make a drop down list for variable value options?

Making a moving platforms class in C++ and I want to be able to select different path shape options for it to move in: Line, Square, and Circle. I want there to be a drop down menu that lets you choose the path in the object details. Then just run the pathing logic through an if statement based on the choice. Is this a possibility?

Yes. What you want is called an enumeration. In a header file you can declare one like so:

UENUM( )
enum class EPathShape : uint8
{
	Line,
	Square,
	Circle,
};

Somewhere in an actor or other UObject you can declare a property:

UPROPERTY( EditDefaultsOnly or EditInstanceOnly or EditAnywhere )
EPathShape PathShape;

And then you can check it either with an if or a switch:

if (PathShape == EPathShape::Line)
{
}
else if ( ... )

switch (PathShape)
{
	case EPathShape::Line: ...
		break;

	...
}