Copy and paste to different worksheets
if your aim is to:


copy the value in cell "B4" of worksheet "Sheet1"
and paste it in worksheets "Sheet2" from cell "A1" downwards in iterations cells


then simply use:

Dim iterations: iterations = 1000    
Worksheets("Sheet2").range("A1").Resize(iterations).value = Worksheets("Sheet01").range("B4").value


if your aim is to:


copy the value from cell "B4" of worksheet "Sheet1" and down to iterations cells 
and paste them in worksheets "Sheet2" from cell "A1" downwards in iterations cells


then simply use:

Dim iterations: iterations = 1000    
Worksheets("Sheet2").range("A1").Resize(iterations).value = Worksheets("Sheet01").range("B4").Resize(iterations).value