As per your query, you have forgotten the password to your TP-Link router, what I am not sure here is whether you forgot the wifi password or the router admin password, so I will discuss the troubleshooting techniques keeping both these things in mind. Follow the given instructions carefully:
- First reset your router since you have forgotten the password, so press the "Reset" button at the back of your router for 20-30 seconds to reset your router to factory settings. This will eliminate and wipe out all the changes made to your router including the password you forgot. Also, make sure not to overdo this step as resetting your router for 5-7 times may cause permanent damages.
- Connect your TP-Link router to your computer using an ethernet cable, one end of the cable goes inside the WAN port while the other end goes inside your computer's ethernet port. Wait for few seconds to let the connection between the two get established.
- Open your web browser and type in your IP address in the given URL field and hit Enter. This will redirect you to your TP-Link router login portal. In case you do not know your IP address then you can simply google,"My IP address" or "Default IP address of TP-Link".
- Enter the username and password for your router settings. In case your ISP did not provide any login credentials then, put "admin" in the username field and leave the Password field blank and hit Enter. This will redirect you to the main settings page of your router.
- Once on the main page, click on "Advanced Settings" > "Security", under the security section change the encryption of your device to "WPA2" as it is considered to be a government graded encryption type. Below the encryption, you will notice a box by the name of "Pass-key" this is your wifi password which you forgot. Change it to a secure and simple enough to remember and save the settings.
- The above methods will help you secure TP-Link router but in case you want to make it impenetrable from outside source, you can use MAC Address filtering. Add the MAC address of the devices you want to grant access to your router under the MAC Filtering option and only these devices will be able to get access to your router.
These methods will surely help you in making your TP-Link router safe and secure against any kind of intruder. Also, make sure to write down your password somewhere so that you can use it later in case you forget it again.