What is meant by le mot de passe doit comprendre au moins une lettre en majuscule?

The phrase "le mot de passe doit comprendre au moins une lettre en majuscule" means "the password must contain at least one uppercase letter".

Here's a breakdown:

* le mot de passe: This is French for "the password".

* doit comprendre: This means "must contain" or "must include".

* au moins: This means "at least".

* une lettre: This means "one letter".

* en majuscule: This means "uppercase" or "capital".

So, the entire phrase is a security requirement stating that your password needs to have at least one capital letter in it.