Built-in Constants

Built-in constants are sometimes referred to as intrinsic constants.

VBA.Constants	Chr	Comments
vbCr	Chr(13)	Carriage return character
vbLf	Chr(10)	Linefeed character
vbCrLf	Chr(13) + Chr(10)	Carriage return - linefeed combination
vbNewLine	Chr(13) + Chr(10)	New line character
vbNullChar	Chr(0)	Character having a value of 0.
vbNullString	String having value 0	Not the same as a zero-length string (""); used for calling external procedures. Cannot be passed to any DLL's
vbTab	Chr(9)	Tab character
vbBack	Chr(8)	Backspace character
vbFormFeed	Chr(12)	Word VBA Manual - manual page break ?
vbVerticalTab	Chr(11)	Word VBA Manual - manual line break (Shift + Enter)

vbNullChar

This constant can be used to test for a null character.
This can also be used for assigning a null character to a string variable.
The vbNullChar constant can be useful when passing string variables to external libraries that require a null-terminated string.
This constant should be used instead of Chr(0).

vbNullString

This constant can be used for assigning a zero-length string.
This can also be used to test for empty strings.
For all practical purposes using a zero-length string ("") is equivalent to using vbNullString.
A zero length string means a string with no characters
vbNullString is a constant used for a null-pointer and is more efficient than a zero-length string
The following four lines are all equivalent.

Dim myString As String 
myString = "" 
myString = vbNullString 
myString = Constants.vbNullString 
myString = VBA.Constants.vbNullString

Other Characters

Chr(14)	Column break
Chr(30)	Non-breaking hyphen
Chr(31)	Optional hyphen
Chr(32)	Space
Chr(34)	Quotation Mark
Chr(160)	Non-breaking space