It’s called World Position. Type position in the search and it should show up. As for Absolute including Material Offsets part, look at the node settings, you can select it there.
If for some reason you still can’t find it, copy the text below, and paste it in your material editor, it should appear.
Begin Object Class=/Script/UnrealEd.MaterialGraphNode Name="MaterialGraphNode_0"
Begin Object Class=/Script/Engine.MaterialExpressionWorldPosition Name="MaterialExpressionWorldPosition_0"
End Object
Begin Object Name="MaterialExpressionWorldPosition_0"
MaterialExpressionEditorX=-224
MaterialExpressionEditorY=240
MaterialExpressionGuid=56EB87FC44927E8BC224BA89756B83CE
Material=PreviewMaterial'"/Engine/Transient.PreviewMaterial_0"'
End Object
MaterialExpression=MaterialExpressionWorldPosition'"MaterialExpressionWorldPosition_0"'
NodePosX=-224
NodePosY=240
NodeGuid=12DC61A3411DBD8E53755BA77B5423EE
CustomProperties Pin (PinId=2D6323DB429D061C87090BA8E74FCB55,PinName="Output",PinFriendlyName=NSLOCTEXT("MaterialGraphNode", "Space", " "),Direction="EGPD_Output",PinType.PinCategory="",PinType.PinSubCategory="",PinType.PinSubCategoryObject=None,PinType.PinSubCategoryMemberReference=(),PinType.PinValueType=(),PinType.ContainerType=None,PinType.bIsReference=False,PinType.bIsConst=False,PinType.bIsWeakPointer=False,PinType.bIsUObjectWrapper=True,PersistentGuid=00000000000000000000000000000000,bHidden=False,bNotConnectable=False,bDefaultValueIsReadOnly=False,bDefaultValueIsIgnored=False,bAdvancedView=False,bOrphanedPin=False,)
End Object