This is the 5635th most frequent Chinese word.
务
"务" means "affairs," "business," or "to attend to."
Here, "务" is used in the term "事务" (affairs), indicating duties or matters that require attending to.
我负责公司的客户事务。
I am responsible for the company's customer affairs.
In this sentence, "务" is part of "务必" (must/ensure), expressing a sense of obligation or necessity.
务必认真完成你的作业。
You must seriously complete your assignments.
This illustrates "务" in "服务" (services), where it refers to the act of providing services or assistance.