需要的信息主要是：姓名，护照号码，职位，薪资。一般还需要休假证明，可以说明下旅游这段时间的假期已被公司批准。下面有个模板参考下：

This is to certify Ms ***** (passport number: **** ), has been a full time employee of *** since ****. Her current position is ****, monthly gross salary is RMB *****.

兹证明**女士，护照号码: **** ，于年

月日加入**公司，职务为***，其月税前收入为****元。

We hope this information would be useful for your issuing a visa to her. If you need any further information, please feel free to contact me at ********.