Informal:
* 괜찮아 (gwaenchana): This is the most common and straightforward way to say "It's okay." It's used with friends and family.
* 괜찮아요 (gwaenchana-yo): This is a slightly more polite version of "괜찮아" and can be used with people you're not as close to.
Formal:
* 괜찮습니다 (gwaenchansseumnida): This is the most formal way to say "It's okay." It's used with people in positions of authority or someone you don't know well.
Other options:
* 괜찮아요 (gwaenchana-yo): This can also be used as a polite way to say "You're welcome."
The best way to choose which phrase to use depends on the situation. If you're unsure, it's always better to err on the side of politeness and use a more formal expression.