What is the social security administration's tax id number?

If it's asking for an EIN number you are entering it in the wrong place. There is no EIN on social security SSA-1099.

Try going to the search box and type in SSA-1099 or Social Security Benefits.  That will give you a Jump To link to take you directly to it.

OR

Enter a SSA-1099, SSA-1099-SM or RRB-1099  under

Federal Taxes on the left side or top

Wages and Income

Then scroll down to Retirement Plans and Social Security

Social Security (SSA-1099. RRB-1099) - click the Start or Revisit  button

Up to 85% of Social Security becomes taxable when all your other income plus 1/2 your social security, reaches:

Married Filing Jointly: $32,000

Single or head of household: $25,000

Married Filing Separately: 0