The HL-LHC will require modifying the machine and infrastructure installations of the LHC in several points along the Accelerator Ring, in particular: P1, P2, P4, P5, P6, P7 and P8. Part of the modifications and improvement in P2, P4, P7 and P8 shall be completed during Long Shutdown 2 (LS2) and be operational for LHC Run 3, while the largest part of the interventions will take place in Long Shutdown 3 (LS3) and they will affect primarily P1, P4, P5, P6 and P7. The activities required point by point will be therefore listed and analysed here below.