This is not smoothed since it’s the standard one, to smooth the Signal line we need to add a smoothing average:

FastMA       = 12      //12  Fast average
SlowMA       = 26      //26  Slow average
Periods      = 9       //9   periods for the Signal
MAtype       = 1       //1=ema   average type(see available types https://www.prorealcode.com/documentation/average/)
SmoothPeriods= 20      //20  smppthing periods
SmoothType   = 1       //1=ema   smoothing average type
MyMACD       = Average[FastMA,MAtype](close) - Average[SlowMA,MAtype](close) //difference of the two averages
MySignalLine = Average[Periods,MAtype](MyMACD)                               //average of the MACD
MySignalLineS= Average[SmoothPeriods,SmoothType](MySignalLine)               //average of the SIGNAL line (smoothing)
//MyHisto    = MyMACD - MySignalLine                                         //hystogram
MyHisto      = MyMACD - MySignalLineS                                        //hystogram (smoothed)
RETURN MyMacd AS "Macd",MySignalLineS AS "Signal",MyHisto as "histo"

you  will set the periods and type of any average as best suits your needs. Expnential averages are used by default.

As you can see from the attached pic, the MACD has the same value as the original, while the Signal line has a smoothed value.

x-2.jpg