1) Let say colomn A is a product codes, such as "PK0021", "UQ05P8", etc...Now
I want add a "Z" in front the codes. To be "ZPK0021, ZUQ05P8". What's the
faster way in case I got thousand of codes?

2) In my colomn B is such code as "18-521-65, 18-81-84, 18-1112-65" and etc.
Now I would like to make it to be standard to 4 digit for the middle number
to be "18-0521-65, 18-0081-84, 18-1112-65" ... As the same senario as above,
I got more than thousand of such codes... What's the faster way?