arduino uno Webserver domain

How do I edit this code to connect to arduino using a domain instead of an ip ?

#include <WiFi.h>

#include <SPI.h>
#include <Ethernet.h>
byte mac = {0x90, 0xA2, 0xDA, 0x00, 0x9C, 0xB7 };
IPAddress ip(xxx,xxx,xxx,xxx);

EthernetServer mojServer(80);

void setup(){
Ethernet.begin(mac, ip);
mojServer.begin(); //spustíme server
}

void loop(){
EthernetClient Klient = mojServer.available();
if (Klient){
boolean prazdnyRiadok = true;
while (Klient.connected() && Klient.available()){
// ak klient odosiela HTTP požiadavku
char c = Klient.read(); //čítaj znaky v bajtoch od klienta

if(c == ‘\n’ && prazdnyRiadok){
Klient.println(“HTTP/1.1 200 OK”);
Klient.println(“Content-Type: text/html”);
Klient.println(“Connection: close”);
Klient.println();
Klient.println("");
Klient.println("");
Klient.println(“Arduino WEB server”);
Klient.println("");
Klient.println("");
// vypíše text
Klient.print(“Ahoj, ja som Tvoj Arduino web server :-)”);
Klient.println("");
Klient.println("");
}

if(c == ‘\n’){
prazdnyRiadok = true;
}
else if(c != ‘\r’){
prazdnyRiadok = false;
/ak klient nepošle dvakrát za sebou \r a \n
znamená to, že stále odosiela dáta
/
}
}

Klient.stop(); //komunikácia je skončená
}
}

"How do I edit this code to connect to arduino using a domain instead of an ip ?"

Generally speaking you need a domain name to do that. Typically people use a dynamic domain name service such as https://www.noip.com/ or similar.

can I overwrite the IP address?

napr www.test.com