Input tax credit not available for material used for construction of factory building for his own account , It's block credit under section 17 (5) of the CGST act 2017 .if you have taken then you have to reverse it with interest .
If the unit are in same state , the said Raw material can be transferred under delivery challan (it's part of process of manufacturing). , But if the units are in 2 different state then raw material need to transfer only by issuing Tax Invoice & is taxable.