How to find whether the record is modified in Salesforce?

CreatedDate and LastModifiedDate fields are date time fields.

These two field values will be same when create a record. If the record is modified, it will not be same since the last modified time will be different from the time created.

Even though the record is modified on the same day, time will be different. So, using these two fields we can easily identify whether the record is modified.

CreatedDate = LastModifiedDate - Record is created.

CreateDate != LastModifiedDate - Record is updated after creation.