Origin decides consent, and consent is the practical difference. A consensual lien exists because the borrower signed a document creating it, so its terms are in a contract the borrower has a copy of and can read. A statutory lien exists because a legislature said it does. Property taxes are the everyday example: the unpaid tax becomes a charge against the parcel itself, and the owner agreed to nothing. Contractors, suppliers and, in some circumstances, homeowners associations also hold liens by statute in many states. A judicial lien is the slowest to arise and the most visible while it is arising, because a creditor must file a lawsuit, serve the defendant, win a judgment, and then take a further step to attach it to property. A borrower surprised by a judicial lien has usually had several opportunities to respond and did not take them.
A lien is against the thing, so it outlives the transaction it came from. This is what separates a lien from an ordinary claim for money. If a creditor simply has a right to be paid, it has to find the debtor and pursue them. A lienholder has a claim on a specific asset, and the asset does not move. That is why a title search before a house purchase is not paperwork but the whole point: a lien recorded against the parcel is generally still there after the parcel changes hands, and a buyer who takes the property without clearing it has bought the problem. It is also why a payoff at closing is handled by the settlement agent rather than left to the seller, and why a release is recorded afterwards showing that the lien is gone.
Not every lien is on the public record, and the ones that are not are the ones that catch people. Recorded real property liens are searchable at the county. A vehicle lien is noted on the certificate of title. But a general contractor's or subcontractor's right to file a lien can exist for a period after the work is done and before anything is filed, and in many states an owner who paid the general contractor is not automatically protected if the general contractor never paid the crew. The lien waiver a settlement agent collects before releasing funds exists to close that gap.
What removes a lien is not always what removes the debt. Paying the obligation is the ordinary route, and a release or satisfaction is then recorded. Where the debt is disputed or defective, state law usually supplies a procedure for challenging or discharging the lien on its own. And in bankruptcy the two come apart entirely, because a discharge erases personal liability while the lien itself generally stays attached to the property, a result that surprises almost everyone who meets it for the first time.