Bankruptcy helps you get rid of unsecured debt. It does not eliminate secured debts, where you have pledged collateral for a loan, such as a car loan or a mortgage. When you file bankruptcy you must declare what you intend to do about your secured debts.
Medical debts are perhaps the most common reason people choose the "fresh start" option that bankruptcy gives them. Illness or injury, combined with loss of income can produce exactly kind of financial stresses that bankruptcy is designed to cure. Rather than be saddled with a lifetime of debt, bankruptcy can eliminate it, and give you a fresh start. Every state ranks differently. Find out how California ranks.
A "reaffirmation agreement" says that your personal liability for a debt goes unaffected by your bankruptcy. But because that's what bankruptcy is for, they should only be signed on rare occasions.
Bankruptcy can eliminate some kinds of debts, like credit card debt and medical debt, but not others, like child support and (in most cases) student loans. And liens associated with "purchase money secured debts", where you have pledged collateral for a loan, also are not affected by a bankruptcy, so you can still lose the collateral to the lien-holder.
By law, child support obligations generally cannot be avoided in a bankruptcy. They pass pretty much intact.
Some kinds of debts pass unscathed through bankruptcy, including child support, debts incurred through fraud or other bad acts, most student loan debt, more.
If you filed tax returns but didn't pay, and the taxes are more than three years old, you may be in luck.
Co-signers will still owe the full amount of the debt, even if you you get your personal liability discharged in Chapter 7 bankruptcy.
Your employer can garnish your wages if forced to do so by court order or federal law. Some debts like child support, taxes, and student loans, do not require a court order.