Here are a few of the Fannie/Freddie common servicers:
If you are uncertain if Fannie or Freddie insure your loan, Check here:
Fannie Mae Loan Lookup: https://www.knowyouroptions.com/loanlookup
Freddie Mac Lookup: https://ww3.freddiemac.com/loanlookup/
If your loan is not insured by Fannie or Freddie, many servicers are offering help check your servicer's site, but here are a few common ones: