ESP3D has several discovery services that help to access your device once connected to your wifi network:
1 - under Windows

a - SSDP
Windows has SSDP protocole (Upnp based)
Just go to network in file explorer and double click on your device listed under Others Devices
you can also check device properties

b - Hostname
If your router provide DHCP you can also use the hostname set on esp3d
type <your hostname>/ on your browser address bar (do not forget the /)

2 - under Linux

a - Hostname and mDNS
type <your hostname>.local on your browser address bar

b - avahi-discover and mDNS
you need avahi-discover
I - ESP3D V2.x check Web Site section of your local network

II - ESP3D V3.x check _esp3d._tcp section of your local network

3 - under OSX

a - Hostname and mDNS
type <your hostname>.local/ on your browser address bar (do not forget the /)

b - mDNS browser
you can use Discovery - DNS-SD Browser
https://apps.apple.com/us/app/discovery-dns-sd-browser/id1381004916?mt=12

I - ESP3D V2.x check _http._tcp (World Wide Web HTTP) section of your local network
II - ESP3D V3.x check _esp3d._tcp section of your local network

4 - under Android

a - Hostname
If your router provide DHCP you can also use the hostname set on esp3d
type <your hostname>/ on your browser address bar (do not forget the /)

b - Service Browser
https://play.google.com/store/apps/details?id=com.druk.servicebrowser&hl=fr&gl=US
I - ESP3D V2.x check _http._tcp (World Wide Web HTTP) section of your local network
II - ESP3D V3.x check _esp3d._tcp section of your local network

c - Bonjour browser
https://play.google.com/store/apps/details?id=de.wellenvogel.bonjourbrowser&hl=en_US&gl=US

Select the device with the ESP3D hostname