If you worked for American companies from abroad, you probably filed W-8BEN and were considered a non-US person for all tax purposes, had no TIN and nothing was reported on you to Equifax or other credit reporting companies (e.g. Transunion or Experian).
If you filed W-9 as US person, you gave them a TIN, which in the majority of employment related cases is your SSN, and then they most likely reported your employment to Equifax.
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The main question is whether you have SSN or not.
If you worked for American companies from abroad, you probably filed W-8BEN and were considered a non-US person for all tax purposes, had no TIN and nothing was reported on you to Equifax or other credit reporting companies (e.g. Transunion or Experian).
If you filed W-9 as US person, you gave them a TIN, which in the majority of employment related cases is your SSN, and then they most likely reported your employment to Equifax.