The most important rule: uniqueness
Bad:
Instagram = Minou2026!
Facebook = Minou2026!
Amazon = Minou2026!Also very bad:
Instagram = Minou2026Instagram!
Facebook = Minou2026Facebook!
Amazon = Minou2026Amazon!The structure is still predictable. Prefer automatically generated passwords, different for every site.
Cybermalveillance.gouv.fr recommends at minimum long and complex passwords when you have to create them yourself.