What does it mean when a bank put a lien on your property and how does it affect your credit

If you have a mortgage with the bank, that mortgage creates a lien and the bank reports your payments on your credit report... keep current, and you keep good credit.

If you don't pay your mortgage, the bank reports that also and people will see that if you can't pay your mortgage, you and your credit are in BAD SHAPE

A lien is an encumbrance on a property that says someone has an interest in that property. Therefore the property cannot be transferred without the lien being statisfied.

When you take a loan out against a property, the lender will place a lien on the property. If you renege on a debt the creditor may be able to place a lien. If a creditor places a lien, its because you have been sued and lost. That will have a negative effect on your credit, the lien itself won't.