how to define variable in vba code example

Example: vba declare variable with value

Dim myString As String:  myString = "aaa bbb"
Dim myStringCaps As String:  myStringCaps = UCase("aaa bbb")
Dim myPart As Variant: myPart = Split(myString)
Dim ws As Worksheet: Set ws = ThisWorkbook.Worksheets(1)
Const MY_CONST As String = "Value"