The basis is Dubai Law No. 7 of 2006 on real estate registration. It lets foreigners acquire full ownership (freehold), usufruct or a leasehold of up to 99 years in designated freehold areas (source: Dubai Land Department; UAE government portal u.ae). Regulation No. 3 of 2006 defines which areas these are.
Freehold means the buyer is registered on a Title Deed as the owner of the unit and its land share, indefinitely and heritably, with full rights to sell, let or alter within the rules. Most locations relevant to international buyers in Dubai, such as Dubai Marina, Downtown or Business Bay, are freehold.
Leasehold is a long-term lease or use right, typically up to 99 years. The leaseholder uses the property while ownership of the land stays with the freeholder. At the end the property reverts to the owner unless it is renewed. For investors, freehold is usually the clearer choice because it is real, tradable ownership.
Which ownership type fits which goal is something we clarify in buying property in Dubai.