"El Día Que Naciste" is a beautiful concept often used for personalized keepsakes, music, or sentimental stories. Since you mentioned "rar" (typically a file compression format) alongside "create post," it sounds like you might be looking to share a specific digital collection or a creative template.
Use a photo of a calendar, a baby's first shoes, or a "On this day in history" newspaper clipping to grab attention.
If you are sharing a .rar link, make sure to mention that the file is virus-free to build trust with your audience.
Hay fechas que cambian nuestra vida para siempre, y el día que llegaste tú fue el comienzo de mi aventura favorita. He recopilado [detalla qué hay en el archivo, ej. fotos, recortes de periódicos de ese día, música] en este pequeño cofre digital.