How to export full size image from Lightroom?

I m working with a print company to blow up 3 images to 10ft l x 8ft w. My print company told me this for "full size" images.

"IF you are looking to do a banner that is 120” x 96”
Make your photo 120” x 96” @ 75 dpi

9000x7200 @ 75 dpi in theory"

My trouble now is exporting from Lightroom and keeping the image full size. I shoot w/ a Nikon d5500 in RAW and edit slightly, so after I click export, what settings should I export at so it s big enough for the print company to make the banner? I m thinking TIFF… And should I save it on desktop, send it in an e-mail or put on the SD card?

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