Once you've set up a Wireguard VPN server, you'll also want to protect your DNS requests. One method of achieving this is to set up a DNS over HTTPS resolver on your VPN server and route your DNS traffic over the VPN tunnel.
How to configure DNS nameservers on Ubuntu 18.04
On most Linux distributions you configure DNS nameservers in
/etc/resolv.conf. However in recent versions of Ubuntu that changed with the introduction of Netplan.