Tax collector
The town official who figures out how much tax each owner owes, sends the bills, takes in payments and enforces late taxes through interest, tax liens and tax sales.
New Jersey example
Say you missed a payment and want the exact amount due with interest. You'd contact your town's tax collector, not the tax assessor. The collector handles billing, payments and late-tax enforcement, working with the assessor and the county board of taxation. The state's Division of Local Government Services certifies tax collectors after an exam.
Official source
This is a plain-English summary. Rules and dollar amounts change, so check the official source or a professional before you file or sign anything.