While Oregon does not have sales tax, Oregon does provide the Oregon Business Registry Resell Certificate to provide evidence a buyer is registered to do business in the state of Oregon.
Please fill out this form if operating in the state of Oregon and upload when registering or adding a location: https://www.oregon.gov/DOR/forms/FormsPubs/or-business-registry-resale-cert_800-002.pdf
For any locations within the state of Montana, please use the Uniform Sales Tax Certificate: https://www.salestaxhandbook.com/pdf/UniformSalesTaxCertificate.pdf
New Hampshire & Delaware
Instead of a resell certificate, please upload a current copy of your local business license.
If you operate within Alaska please upload this letter as your resell certificate: http://doa.alaska.gov/dof/acct/resource/tax_exempt_letter.pdf