You can custom format numbers but not alphabets

To convert 12345 go 12-345 use 00-000

To get what you want you will need to have alphabets and numbers in separte
columns and then join them.

"Forms document" wrote:

How do I format a cell from B802412M07 to B-80241-2-M07. I know how to do it
with a formula but is there a way to just custom format the cell?