In your case, Instagram usually says: “We’ve detected suspicious activity on your Instagram account and have temporarily locked it as a security precaution.”
Note that It’s likely that your account was compromised as a result of entering your password on a website designed to look like Instagram. This attack is known as phishing.
You don’t need to worry right now because Instagram normally lifts the ban after 48 hours. And you don’t need to do a thing in most cases. But if, after 48 hours, the ban is still in place, you need to submit a form to recheck the issue and verify yourself.