Yes you can donate your car to Habitat For Humanity as long as you have the title to the car you're donating.
Habitat for Humanity will then take your donated car and sell it to someone or someplace and then use the proceeds of the car sale that you donated to them for covering the cost of the work they do.
In some cases your donated car may quality you for an income tax deduction.
So if you donate your old car to Habitat for Humanity then you should check with them and your income taxes to see if your donated car qualifies you for an income tax deduction.
So donating your car to Habitat for Humanity or any other donated car charity can save you money on your income taxes and you'll be doing a good thing donating your old car and getting rid of your old car in the process.