委托外协设计用英语可以说作"outsource design".

这个短语来自英语单词"outsource", 意思是将某项任务或工作外包给外部供应商。加上"design"一词，就表示将设计任务外包给外部供应商。

例句：

We decided to outsource design to a local agency because they had more experience in the field.
(我们决定将设计工作外包给当地一家机构，因为他们在这个领域有更多经验。)
The company has been outsourcing design to save money and improve efficiency.
(公司一直在外包设计工作以节省成本和提高效率。)
Many companies are outsourcing design to take advantage of the expertise and lower costs offered by foreign designers.
(许多公司都在外包设计工作，以利用外国设计师提供的专业知识和较低的成本。)