Is the label waterproof if I print with an inkjet printer? Thank you!

The Integrated Forms are not waterproof whether using with an inkjet or a laser printer. I have included a link below to another product that is the same size label and available in our weatherproof material options. https://www.onlinelabels.com/OL369.htm

I use PayPal for my online business. Will I be able to print the shipping label and packing invoice all on one sheet with these? How would that work and would anyone know how to set it up? Right now I am using a dymo label printer and still having to print the packing slips then cut and put in order.

The OL1569 is an integrated form intended for printing a packing slip along with a shipping label. The platform you are using to create your labels and packing slips should have this layout option. If not, you should be able to contact them directly if a custom configuration is needed.

are these forms perforated

Yes, the OL1569IF - 7.375" x 4.5" PayPal Integrated Shipping Forms do include a horizontal perforation in the middle of the sheet.

What type of paper is on the non-label side? Is it the same sticker paper?

The Integrated Form (IF) material is uncoated paper throughout the sheet, however, the adhesive is only applied to the section of the sheet including the 7.375" x 4.5" label.