@Rajumustafiz 

For most new Archer Router models, you were asked to set an admin password when you access the web management interface for the first time.

For a few older Archer Router models, the default username and password are both "admin".

If you have completely forgotten the admin password, there is only one way to retrieve it: resetting the Router back to factory default.

To reset the Router, please press and hold the reset button on the Router's back panel using a pin until the light flashes.