You can export static mesh data into Reality API. Static meshes can be used with geometry objects.
Click EDIT → PROJECT SETTINGS on Reality Editor.
Scroll down, click Export on Reality tab.
Click ➕ under Static Meshes category. Expand the index. Select Static mesh. You can give a name to the Static Mesh. Close the Project Settings window.
Launch Reality Control and press F7 to launch Reality Setup.
Click PLAY on Reality Editor.
Open the nodegraph. Right-click on space, Click CREATE → GEOMETRY → GEOMETRY MESH
Click GeometryMesh node. You can select static mesh that is exported on Reality Editor.