US Immigration from Andorra

Board officer doesn't provide I-94 or stamp on passport. How do I prove my legal entry?

In part 3 of I-485, about I-94 or nonimmigration visa, can I put N/A?

When you fill out part 3 of I-486, what if I don't have I-94 and visitor visa?

Canadian citizen doesn't require B2/B1 visa and I-94 form when they enter USA.

They don't put stamps on passport when travelling by land.

can I leave it blank?

Does anybody have this experience of filing I-485?

I am Canadian citizen to applying I-485 in US

As a initial evidence, I have to show I entered US legally. I entered US by land , so they didn't put any stamp on my passport. What else document I can show to prove the legal entry?

Thank you.