You can connect to the ESP directly, using it as an AP, or let the ESP connect to a different AP. You can use mDNS to open the webpage, by browsing to http://esp8266.local.
All files are stored in the ESP's SPIFFS, and you can upload new files, or update files via a web interface.
You can also use the OTA service to upload new firmware (sketches) over Wi-Fi.
I also advise you to read here: https://randomnerdtutorials.com/esp8266-nodemcu-websocket-server-arduino/
Good luck finding solutions