I withdrew money from my 401K to purchase a home but I didn't specify it as a hardship withdrawal. Can I change that so if reduces the amount of tax I pay

You misunderstood what you are allowed to do with money you took out of a 401k.  An early withdrawal from a 401k for the purchase of a house is NOT an exception to the 10% early withdrawal penalty.  There is such an exception for an early withdrawal from a traditional IRA, but not from a 401k.  So if you were younger than 59 1/2 when you took the money from your 401k, you are subject to the 10% penalty and ordinary income tax on the distribution from the retirement account.

Enter your 1099R :

Go to  Federal> Wages and Income>Retirement Plans and Social Security>IRA  401 k) Pension Plan Withdrawals to enter your 1099R