Secured debt is any debt secured by property that your creditor can take if you fail to make your payments. Your mortgage is a secured debt and so is a car loan. This is called collateral. Lenders place a lien--which is a right to take back their property if you default--on secured debt. You do not own anything loaned to you until your debt is paid in full.
Unsecured debt is debt that is not secured by a property. This debt includes credit card bills, taxes, child support, or spousal support. Creditors cannot take anything from you in these cases because there is no asset attached to your loan. To incite you to pay your unsecured debt, creditors will have debt collectors call you. They may even take you to court, and they will report your unpaid loans the credit bureaus, which keep a record of your credit score. This will reflect poorly on your credit report.
If you are experiencing financial hardship, make sure to be consistent with your most important payments: secured debt. Otherwise, you risk losing your house. You can make the minimum payment on your unsecured loans. However, this means it will take you longer to pay them off, but it is better not to fall behind. Paying the minimum is better than paying nothing.