One way:
Sheets("Sheet2").Range("A1").Value = _
Sheets("Sheet1").Range("A1") & " " & _
Sheets("Sheet1").Range("A2")
which can be shortened a bit:
With Sheets("Sheet1")
Sheets("Sheet2").Range("A1").Value = _
.Range("A1").Value & " " & .Range("A2").Value
End With
or even
With Sheets("Sheet1").Range("A1")
Sheets("Sheet2").Range("A1").Value = _
.Value & " " & .Offset(1, 0).Value
End With
Note that you almost never need to select or activate a range in
order to work with it. Using the range object directly makes your
code smaller, faster and, IMO, easier to maintain.