To change your DNS server, go to your device's network settings, find your current connection, and manually enter the IP addresses for your preferred and alternate DNS servers. The exact steps vary by operating system, but you will generally need to find a "DNS server assignment" or "DNS" setting within your network adapter's properties and change it from "automatic" to "manual".
On Windows
Go to Start > Settings > Network & Internet.
Select your active connection (Wi-Fi or Ethernet).
Click Hardware properties.
Scroll to "DNS server assignment" and click Edit.
Change the setting from "Automatic" to Manual.
Toggle IPv4 to On and enter your preferred and alternate DNS server addresses (8.8.8.8 or 8.8.4.4).
Click Save.
On Android
Go to Settings > Network & Internet.
Tap Wi-Fi and then tap on your current network.
Select Modify network or tap the gear icon, and then enable Advanced options.
In the "DNS" field, enter the new DNS server IP addresses (8.8.8.8 or 8.8.4.4).
Tap Save or Apply.
On macOS
Open System Settings and go to Network.
Select your active network connection from the list on the left.
Click Details or Advanced.
Navigate to the DNS tab.
Click the + button under "DNS Servers" to add a new address.
Enter the IP addresses for your new DNS servers (8.8.8.8 or 8.8.4.4).
Click OK and then Apply to save your changes.