You have to carry the following documents for the H1B visa interview. You have to split the documents as two types one as Mandatory documents and the other as Supporting documents. So you will keep the Mandatory documents in one cover and the supporting documents as another cover. It will help and easy to find the documents at the time of interview.
1. Current passport and old passports
2. DS-160 Confirmation page
3. Original interview appointment letter
4. I-797 Original and one copy
1. Recent letter from Client.
2. Recent letter from Employer.
3. Work experience letters
4. Last 3 months Pay slips
5. Original degree certificates
6. Photo copy of your passport (all pages)
7. Carry if you have W-2 forms
8. Carry onsite Manager Name and contact details
9. Your Resume
10. Employment broacher and Employment contract letter.
11. Labor Condition Application (LCA)
12. One photograph
Remember your passport number.