How do I locate or track down old w2s? I need to file returns for the past 3-5 years in which I would have received a refunded amount on taxes I paid in .. I do not owe

Looking for all my past w2 tax forms so I can file and be current/up to date as I am looking to to be the sole proprietor of my own business. Does the irs have copies of all my employers earning statement I assume they have to send us the same copy of a w2 as the company sends the irs