Copying Data from one Excel sheet to three different ones

Hi, you can try this:

using XLSX

# CREATE INPUT DATA:
XLSX.openxlsx("origin.xlsx", mode="w") do xf
    sheet = xf[1]
    XLSX.rename!(sheet, "origin")
    sheet["A1", dim=1] = collect(1:3000)
end


# PRODUCE 3 ADDITIONAL SHEETS:
XLSX.openxlsx("origin.xlsx", mode="rw") do xf
    XLSX.addsheet!(xf, "1")
    xf["1"]["A1"] = xf["origin!A1:A1000"]
    XLSX.addsheet!(xf, "2")
    xf["2"]["A1"] = xf["origin!A1001:A2000"]
    XLSX.addsheet!(xf, "3")
    xf["3"]["A1"] = xf["origin!A2001:A3000"]
end