Is it permissible to finance a partner from Abu Dhabi for computer parts deals at a rate of 4% of the merchandise value, due 45 days after its arrival in Yemen, and what is its legal ruling in Islamic law?

If the financier buys the goods and takes full possession of them, then sells them to the buyer for an agreed-upon profit, this is permissible according to Islamic law and is a type of murabaha sale. However, if the financier only pays the money without buying the goods himself or through his agent, and then this money is repaid to him with an increase, this is not permissible and is considered usury (riba), whether it is paid to him upfront, deferred, or in installments. A murabaha sale is a sale at cost price plus a known profit.