GIT/REP forms
New Jersey income tax forms that must be filed to record the deed when property is sold. Residents file GIT/REP-3. Nonresident sellers generally prepay estimated tax at closing: 10.75% of the gain or 2% of the price, whichever is more.
New Jersey example
Made-up example: a seller who lives in Pennsylvania sells a Cherry Hill rental house for $300,000 with a $50,000 gain. 10.75% of the gain is $5,375, but the minimum is 2% of the price, $6,000, so $6,000 is paid at closing. If that is more than the tax owed, the seller can claim the extra back on Form A-3128 or the NJ-1040NR return.
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.