What if i bought a car? And what do i need to do if i have filed bankruptcy?

As to your car question:

Please visit Cars and Other Things You Own and Sales Tax in Deductions and Credits- you may be able to deduct some items associated with the car.

1. Federal Taxes 
2. Deductions and Credits
3. Scroll down to Cars and Other Things You Own   
4. Then, scroll down further to Estimates and Other Taxes Paid and select Sales Tax to enter sales tax paid on the purchase.

 Note: Above deductions are part of your itemized deductions. If you don't claim mortgage interest, real estate taxes, your car deductions will not make a difference on your tax return.

As to your bankruptcy question:

You won't receive a form showing a bankruptcy in itself.  And in general, bankruptcy will not have an impact on your income tax return; any debts that are discharged in bankruptcy are excluded from income.

You may receive a form 1099-C from one of the creditors, it will indicate a bankruptcy discharged debt.  Please be sure to report the form 1099-C and file form 982, which shows the debt was relieved in bankruptcy (it is recommended to use the Cd/Download product of Turbo Tax if that's the case or to contact one of your local tax professional to help you review your situation).