Customizing invoice and packing slip

[Jatt]

How can I customize my invoice and packing slip?
I'd like to remove some columns and change the logo and title at the top

And where can I change the default text in the emails sent to the customer when they place an order and when this order is shipped?

[DucatiMondo]

You can change the logo on both the invoice and the packing slip easily by copying your logo of choice to the following place

/catalog/admin/images/logo.gif

That is the Zen-Cart logo that appears on the packing slip and invoice. The original logo size is 234px x 60px. So if you make your new logo size the same then it will not mess the template up by just replacing that file. The same logo.gif is used for both templates.

You can switch on or off various columns in the invoice page by looking in the admin area in Modules=>Order Total

For the email help, I don't know as I am having a few problems with having emails sent out myself.