Can you file the MI-1040CR-7 form for the michigan home heating tax credit?

Yes, the form is available in TurboTax and can be E-filed with your return.  TurboTax will collect your relevant information when you're working in the state portion of the program.

It sounds like you're having trouble finding where to enter your credit information in the Michigan portion of TurboTax.  To get to this section in TurboTax Online: 

1. Select Tax Home in the left pane
2. On the  Hi, let's keep working on your taxes! screen, select the dropdown on the right side of the State Taxes box, then select Start, Continue, or Review/Edit
3. If the  You've already got a head start on state taxes screen appears, select Let's get started.  Otherwise, in the left pane, select Your State Returns
4. Proceed through the screens until you come to the Status of your state returns screen
5. Select  Start, Continue or Edit to the right of Michigan
6. Proceed through the state screens until you get to the Take a look at Michigan credits and taxes screen
7. Select  Start to the right of Home Heating Credit
8. Go through the following screens, entering any information necessary

You don't need to send Form MI-1040CR-7 separately from your Michigan return, if you're filing a state return.

If you aren't required to file an MI-1040, you can file your Home Heating Credit Claim by submitting form MI-1040CR-7 only.  You would mail your claim to: 

Michigan Department of Treasury 

Lansing, MI 48956 

See the MI-1040CR-7 Instructions available at Home Heating Credit Information for more filing information.