How to synchronize my macOS calendar with my iOS devices' calendar

Hi, I know that I have to go through iCloud to synchronize my calendars. But, on my iMac, on the left, I have a list corresponding to my accounts. The first one is iCloud with the Calendar option (Calendar, Family, Home). The option Calendar is checked. I have another account corresponding with the choice with my Apple ID, and it checked. But what I put in my calendar on macOS is not synchronized with my iOS devices (iPhone and iPad). What do I do wrong? I want all my calendars (iOS and macOS) to be the same. Any ideas? Thanks.