Inserting Dashes between Letters and Numbers

VBA scripts assume the data of "myText" is to be accessed as the attribute ".VALUE"
and that may do conversion of entries that look like dates to be held as the numeric version - dayNUMBER and fractional part of the day for a timestamp so it's no longer text
Also it may take a number that appears to be in a currency format cell to be USD, and - round it to 2 decimal places ( maybe bankers rounding !) and add a preceding "$" so it's a text value !

Maybe force Formula result to be text by preceding the generated, or intermediate results with ""& stops the formula/function generating 0 for ,"", and ,,
and in VBA specify .VALUE2 to avoid the unwanted Excel processing !

But do check that functions in the excel sheet do not fail when processing empty cells that are "void text strings" rather than 0

It may also be appropriate to check that
your added "-" is not being added where there was already the needed "-", so generating "--"
and that adding the "-" does not get Excel to consider that value as a negative number,
and that the Excel considering the value as a number has not removed leading "0"'s, or imbedded "," or ".", or "E" meaning scientific number entry ,
and that - for your location, language, date the "-", or "/" are treated as meaning it is a dd mm, or mm dd structured date.
Maybe use TRIM on the data - or maybe keep extra whitespace - within as well as at the start and end of a string,
and there is the growing propensity to use unicode to put graphics in data fields as text characters - changing the just typed set of characters e.g. 1F697 with a unicode character by pressing ALT, and then X to get 🚗
and that works for filenames even getting leading spaces with " 🚗"
and ... ... that sort of thing works with excel sheet tabs too !

Finally - in this response -
A first character of "'" denotes a text value is being entered into a cell, and sometimes that confuses VBA where the data seems to get a an extra "'" added so the value being processed contains a leading pair of of apostrophe's on the text string , and "^" may be taken as meaning Text, and to be centred in the cell !

From experience, Data Cleaning and standardisation is not always simple !
and that's with just the expected language and codepage settings !

As mentioned in a previous post, the flash solution works. A formula can also be used:
=LEFT(A1,MIN(FIND({0,1,2,3,4,5,6,7,8,9},A1&"0123456789"))-1)
& "-" &
MID(A1,MIN(FIND({0,1,2,3,4,5,6,7,8,9},A1&"0123456789")),99)
Power query also works:
let
InsertDash = (code as text) =>
let
pos = List.PositionOfAny(Text.ToList(code), {"0".."9"}),
result = if pos > 0
then Text.Start(code, pos) & "-" & Text.Range(code, pos)
else code
in
result
in
InsertDash

Then add a custom column using InsertDash([ProductCode]).

Avoids having to use macros.

ASAPUTILITIES has a couple of functions that would work here:-
ASAPSTRIPNUMBERS() will remove the digits and ASAPEXTRACTNUMBERS() will remove the alphacharacters, so

=ASAPSTRIPNUMBERS(A1)&"-"&ASAPEXTRACTNUMBERS(A1)

would do what is required

I Think I'm inching close: How can I do this in Word?

Instead of those complicated formulas, I prefer a user defined function. Here is a much shorter one:

Function DashIn(myText As String)
Dim i As Integer
For i = 2 To Len(myText)
If IsNumeric(Mid(myText, i, 1)) Then
myText = Left(myText, i - 1) & "-" & Mid(myText, i)
Exit For
End If
Next i
DashIn = myText
End Function

Much more easy to do with regular expressions.
Go to http://www.codedawn.com/excel-add-ins.php and install RegEx Find/Replace.

With the product codes in column A,
type =RegExReplace(A1,"([a-zA-Z]+)([0-9]+)","$1-$2") in cell B1, and copy down the formula.

The search field:
([a-zA-Z]+) is first "token", i.e. one or many letters.
([0-9]+) is the second toke, i.e. one or many digits.

The replace field indicates that token $1 is concatenated to "-", then to the token $2.

In Excel 2013, the new Flash Fill feature does what is requested virtually automatically. It even handles the case where there are different numbers of letters, i.e., A4, BR16, P33, etc.

Make sure you have uniquely formatted column headers. Select the cell next to the first data entry, and type "A-4". Now, on the Data tab, in the Data Tools group, click on the Flash Fill icon. The second column will contain "BR-16", "P-33", etc.

As Arthur C. Clarke said, "Any sufficiently advanced technology is indistinguishable from magic."

See the tutorials that come with Help on Flash Fill.

The first suggested formula can be much shorter - something like:

=REPLACE(A1,2,,"-")

Michael (Micky) Avidan
“Microsoft® Answers" - Wiki author & Forums Moderator
“Microsoft®” MVP – Excel (2009-2014)
ISRAEL

I am thankful for the macro code. I will leave the array formula for Excel Ph.D.'s working on a post Doc.

In the macro, using the Boolean function IsNumeric(sChar) will simplify the test for a numeric character. It returns TRUE if sChar is a character that can be converted to a numeric.

If IsNumeric (Mid(myText, i, 1)) Then...