Bay' al-Mu'ajjal means "sale with deferred payment". The seller delivers the goods immediately, but the buyer pays later — either in a lump sum or in installments at a future agreed date.
For example, an Islamic bank buys a car and sells it to a customer at a marked-up price with payments spread over 3 years. The markup replaces interest — the total price is fixed upfront and does not change regardless of when payments are made.
This is one of the most common structures in Islamic consumer financing. The key Shariah requirement: the price, delivery date, and payment schedule must all be clearly specified at the time of the contract.