Is there a way to add and show quantity total on the invoices and packing slips. We currently are manually adding the quantity and writing it in by hand on the invoice. Our previous accounting software would do the count and even gave us a total weight.  Is this possible.

It seems to me that you are using the "Professional Services" version of the invoice... you may wish to change to the retail version instead. It lets you add the quantity of items and will multiple the quantity by the unit price. There are three different versions of invoices. Switch to another version by selecting the drop-down list in the top middle of the invoice form (just under and to the right of the payment method.)

It will not, however, provide the weight. But you can add that to the additional description line for the invoice and print it where you wish.

Let me clarify.  I get the quantities on the individual lines, but we would like a grand total of all the quantities to show at the bottom so that a packing slip or invoice show the customer the total number of boxes they are receiving. Is this possible?

You cannot do this with the internal form designer.  It can be accomplished using Crystal 8.5 to modify the default template supplied with Simply because Crystal can do the formulas.