Identity theft is the act of stealing a person's identity, and using their information for the purposes of fraud.
The information an identity thief needs can be found in a variety of ways. A thief could look at social media accounts to find your full name, and links to the accounts of your friends and family, and posts wishing you a happy birthday will reveal your birth date and often how old you are. Online resumes can provide information on past and present employers, and possibly your address and phone number. If you have a blog (especially one used as an online diary or journal), you may have published a gold mine of personal details.
Once a person has enough details about you, they may use it to access your online accounts. For example, if your email address appears on a social media site, a thief could go to the email site and click a Forgot Password link, which might present a security question asking for your mother's maiden name, your hometown, or the name of your pet. Once they gain access to the account, they can read emails from sites you have accounts with, see monthly statements emailed to you, view your contacts, and see other information that may be useful. If they choose to try and gain access to a financial account (such as one accessed through a credit card or banking site), they might transfer funds or use the account numbers to make unauthorized charges.
Using strong passwords, nonstandard security questions and answers, and two-factor authentication whenever possible helps to prevent potential hackers from easily accessing your accounts. Limiting what information is available online, by being careful what you post, and not filling out any optional fields on accounts and forms will also limit what a hacker is able to see if they gain access.
You should also control what information people are able to acquire through physical means. If someone in your home or workplace can get a hold of your purse or wallet, they could quickly steal the information from there. If they're not locked or secure, any national identity cards, passports, or other documents in your home could be stolen by someone working or visiting your home.
(Sammons & Cross, 2017)