You can contact your current, or former, employer's HR department. They should have a person designated as the plan administrator. They are the go to person in the company for the 401k. If you have received a statement from your 401k plan, there should be a phone number or address of whom to contact with questions.
Michelle, just contact HR at your former employer and ask for the phone number of the plan administrator. As the name implies, the plan administrator actually administers the accounts.
Hi there thanks for reaching out. You need to contact the human resources department of your former employer or the investment provider of the 401(k) plan. The contact information for the 401(k) provider can be found on your statements if one of those is available. Feel free to contact me via email to continue the conversation.