@AHMEDGAMAL 

Hi, for your issue, please take the below answer as reference:

If the default password is to log in the management page of TL-WR743ND, you can try with our default Username and Password which both are admin in lower case letters to check if it works.

If it doesn't work, it means that you may have changed the login username and password before.

Then you need to reset it to be default factory settings, use admin to login the management page again to set it up to make it work

Note: With the device powered on, use a pin to press and hold the RESET button (about 5 seconds) until the system LED becomes quick-flash from slow-flash. And then release the button and wait the Router to reboot to its factory default settings.

If the password you wanted is not login password, please tell us your issue in detail.

Look forward to your reply.