If you are looking for school-related "electronic diaries" (Электронный дневник), these are usually official government or school services:
Скачать электронный дневник МЭШ - Госуслуги lichnyi dnevnik skachat programmu
Most modern personal diaries are available across multiple platforms, offering features like password protection, mood tracking, and photo attachments. If you are looking for school-related "electronic diaries"