There you go (thanks to Nicolas’ post https://www.prorealcode.com/prorealtime-indicators/daily-weekly-monthly-pivot-points/):

Once Mode              = 1                //0, 1, 2 or 3
Once lastMonthBarIndex = 0
Once monthlyHigh       = undefined
Once monthlyLow        = undefined
Once monthlyPivot      = undefined
Once monthlyR1         = undefined
Once monthlyS1         = undefined
Once monthlyR2         = undefined
Once monthlyS2         = undefined
Once monthlyR3         = undefined
Once monthlyS3         = undefined
If Month<>Month[1] then
    monthlyHigh = Highest[BarIndex - lastMonthBarIndex](High)[1]
    monthlyLow = Lowest[BarIndex - lastMonthBarIndex](Low)[1]
    lastMonthBarIndex = BarIndex
    If mode = 0 then
        monthlyPivot = (monthlyHigh + monthlyLow + Close[1]) / 3
    Elsif mode = 1 then
        monthlyPivot = (Open + monthlyHigh + monthlyLow + Close[1]) / 4
    Elsif mode = 2 then
        monthlyPivot = (monthlyHigh + monthlyLow + Close[1]*2) / 4
    Else
        monthlyPivot = (Open*2 + monthlyHigh + monthlyLow) / 4
    Endif
    monthlyR1 = 2*monthlyPivot - monthlyLow
    monthlyS1 = 2*monthlyPivot - monthlyHigh
    monthlyR2 = monthlyPivot   + (monthlyHigh - monthlyLow)
    monthlyS2 = monthlyPivot   - (monthlyHigh - monthlyLow)
    monthlyR3 = monthlyR1      + (monthlyHigh - monthlyLow)
    monthlyS3 = monthlyS1      - (monthlyHigh - monthlyLow)
Endif
Return monthlyPivot coloured(0,0,255) as "mP",monthlyR1 coloured(0,0,255) as "mR1", monthlyS1 coloured(0,0,255) as "mS1", monthlyR2 coloured(0,0,255) as "mR2", monthlyS2 coloured(0,0,255) as "mS2", monthlyR3 coloured(0,0,255) as "mR3", monthlyS3 coloured(0,0,255) as "mS3"

name it “MonthlyPivots”, then call it in your screener:

monthlyPivot,monthlyR1,monthlyS1,monthlyR2,monthlyS2,monthlyR3,monthlyS3 = CALL "MonthlyPivots"

it will return the 7 variables representing Monthly:

1. Pivot
2. Resistance1
3. Support1
4. Resistance2
5. Support2
6. resistance3
7. Support3