Manufacturers set both the account username and password at the factory. The username is often simply the word admin or administrator. The password is typically empty (blank), the words "admin," "public," or "password," or some other simple word.
To improve the security of a Wi-Fi network, you should change the administrative password on your wireless access point or router immediately when installing the unit. The default passwords for popular models of wireless network gear are well-known to hackers and often posted on the Internet. Most devices do not allow the administrative username to be changed, but if yours does, seriously consider changing this name as well.
Finally, to maintain home network security in the future, continue changing this administrative password regularly, not just one time. Many experts recommend changing passwords every 30 to 90 days. Use words that would be very difficult for others to guess.