Subject: Join Me for a Birthday Celebration!

Dear [Friend's Name],

I hope this message finds you well. I am writing to invite you to my birthday party! It’s not every day we get older, so I thought we should celebrate together. The party will take place on [Date] at [Time]. The venue is [Venue Address]. Your presence would mean a lot to me as we create some unforgettable memories. Hope to see you there!

Warm regards,
[Your Name]