Social Security mails SSA1099 in January. If you cannot find it:
GET SSA1099
https://www.ssa.gov/faqs/en/questions/KA-01723.html
Go to Federal> Wages & Income>>Retirement Plans and Social Security (SSA1099 and 1099RRB) to enter your SSA1099.
If you don't have an account with Social Security, you can create one. Once you log into your account, you can see your SSA-1099.