Every – each/each one individually
All – each, everything, any/all together, in total
We use EVERY + SINGULAR NOUN
Every student doesn't like homework. – Each student does not like homework.
Every country has a national flag. – Each country has a national flag.
Every person is important. – Each person is important.
We use ALL + PLURAL NOUN
All students don't like homework. – All students do not like homework.
All countries have a national flag. – All countries have a national flag.
All people are important. – All people are important.
EVERY DAY and ALL DAY
EVERY DAY = ON ALL DAYS
Bill watches news every day. – Bill watches the news every day. /each 1 day/
It's raining every day this week. – It's raining every day this week. /from Monday to Sunday/
ALL DAY = THE COMPLETE DAY
Bill is watching news all day. – Bill is watching the news all day. /from the beginning to the end of the day/
It's raining all day. – It's raining all day. /throughout the entire day/