Dear ( Numele invitatului)
I would like to inform you that this Sunday I will have a party while my parents are on their trip. The party will be at ( ora la care se va da petrecerea) o'clock.
I bought lots of food, there will be music, and I also invited my other friends too, many of them. It would be terrific to see you at my party too, it was a long time since we last hanged out, so this would be a nice way to have some fun together! I hope I'll see you on my party, and I hope you won't dissapoint me by not showing up! I'll be expecting to see you on Sunday!