In-place elements are custom elements that are created in the context of a project.
When you open a Revit project in Revit LT, in-place elements may be included.
Using Revit LT, you can move and modify in-place elements. However, you cannot create in-place elements in Revit LT.
The exception to this rule is in-place walls. You can create in-place walls in Revit LT.