HONG KONG—Chinese telecommunications equipment firm Huawei said Monday that it has reached an agreement with HSBC in Hong Kong to obtain documents that its chief financial office Meng Wanzhou hopes will help prevent her extradition to the United States. Meng, who was detained in Canada in 2018 at the behest of U.S. authorities, has been fighting a legal battle over the last two years as the United States seeks to extradite her over allegations of bank fraud and violations of sanctions against Iran. The United States accuses Huawei of using a Hong Kong shell company called Skycom to sell equipment to Iran in violation of U.S. sanctions. It says Meng committed fraud by misleading HSBC about the company’s business dealings in Iran. An earlier request by Meng’s legal team for documents from HSBC was rejected by a court in Britain. In a court hearing Monday, Hong Kong High Court judge …