Dear Kasia,
I would like to invite you to my birthday party next saturday, the party will be at my house from 3 p.m. to 10 p.m.. There is going to be a big cake and a lot of other snacks, almost all of my friends already told me they are comming so I really hope you can come too, it will be a lot of fun. The party isn't formal so you can dress casually. Write back to me soon!
XYZ
