Adding additional formatted cells using user input

Here is a macro that could work for you. In order to have it run, you just need to name cell D4 as "Top_Left_Corner". The macro uses this named range as a reference.
I've put the inputbox inside the Resize function. If the user click on Cancel, the macro will make no change in this dimension.

Sub Expand_Table_To_User_Needs()
'
    Range("Top_Left_Corner").Offset(-2, 0).Resize(2).Select
    Selection.Copy
    On Error Resume Next
    Range("Top_Left_Corner").Offset(-2, 0).Resize(2, InputBox("Enter number of columns needed", "NUMBER OF COLUMNS", 5, 300, 300)).Select
    Selection.PasteSpecial Paste:=xlPasteFormats, Operation:=xlNone, _
        SkipBlanks:=False, Transpose:=False
    Selection.DataSeries Rowcol:=xlRows, Type:=xlLinear, Date:=xlDay, Step _
        :=1, Trend:=False
    
    Range("Top_Left_Corner").Offset(0, -3).Resize(, 3).Select
    Selection.Copy
    Range("Top_Left_Corner").Offset(0, -3).Resize(InputBox("Enter number of rows needed", "NUMBER OF ROWS", 5, 300, 300), 3).Select
    Selection.PasteSpecial Paste:=xlPasteFormats, Operation:=xlNone, _
        SkipBlanks:=False, Transpose:=False
    Selection.DataSeries Rowcol:=xlColumns, Type:=xlLinear, Date:=xlDay, _
        Step:=1, Trend:=False
    Range("Top_Left_Corner").Select
End Sub