I'm going to have my fourteenth birthday party at my house on Nanchang Street. I think it will be great if you can join us. (开篇概述邀请函事由)
The party is going to start at 2:30 p.m. and end at 5:00 p.m. on Friday. You can take the No.6 or No.12 bus here. John is coming. I think you must be happy to meet him. (描述派对的相关信息)
If you can't find my house, please call me at 8523-9626.(给出了具体的联系方式;运用了if引导的条件状语从句)
Come and have a good time! (再次发出邀请;字迹工整)