Everyday and every day seem to be the same that’s why they are inter changed often in written English.
Both everyday and every day are correct, but they mean different things.
Everyday
Everyday, written as one word without space between every and day is an adjective. We use it to describe something that is seen or used every day. It describes an action or item that’s commonplace or something that you do as a matter of habit or routine.
It describes something that’s very common, like an everyday occurrence.
It means “ordinary”, regular, normal or “typical.”
Everyday clothing,” then, refers to the ordinary clothes you wear on regular days.
Remember one thing about everyday that it’s an adjective so it will come before a noun.
Examples
1. Problems are the part of everyday life.
2. I’ll wear everyday clothes for this party.
3. The phone calls are an everyday occurrence.
4. Bread and butter is an everyday breakfast for us.
Every day
“Everyday” (one word, no space) is an adjective describing something that’s very common, like an everyday occurrence.
On the other hand, “Every day” (with the space) is an adverbial phrase that means each day. It refers to an event that happens daily.
Because of that space, “every” is simply an adjective modifying the word “day.”
If you pair every with any other word, it means each—every day means “each day,”
Examples
1.I teach English every day.
2. She goes to office every day.
