VNAV PATH before the coded approach
If you are downwind on a heading and you execute a course intercept to the initial approach fix ( two ways to do that using the APP/DEP page or Legs page FF twice and add a course) and the initial approach fix has a hard altitude not a 4000A for example the VNAV path will be flown providing the SPD window is closed and the FMA is VNAV PTH. For this to happen nicely you need to input speeds and remove A from the altitude constraints, there are a number of variables to this and it would take some time to explain, the variables are reduction in speed, if the aircraft is flying VNAV SPD then it is speed on elevator and may require thrust to stay on profile being generated by FMC. There is lots more to VNAV but when understood works really well.