明天到总部参加培训英语

参加培训attend a training参加培训的人trainee

参加英语培训课程take an English improvement classetake an English training program

attend training programs

正式的邮件中不要用缩略词 don't要写成 do not.如果是免费午餐,建议说明。如：There will be a free lunch for you tomorrow.If you do not need lunch ,please contact me with e-mial before 9:30a.m. 5th June.2017.Look forward to your arrival。整体语法还行，就是有点Chinglish建议再写英文时可以参考下谷歌翻译的翻译结果。