Refer below Tutorials "ESP8266-NodeMCU FileSystem":- Visit for simillar projects at https://microdigisoft.com
Tutorial 1: ESP8266 NodeMCU LittleFS Filesystem in Arduino IDE----https://microdigisoft.com/esp8266-nodemcu-littlefs-filesystem-in-arduino-ide/
Tutorial 2: LittleFS with ESP8266 to Read, Write and Delete Data on 16X2 LCD Display---https://microdigisoft.com/littlefs-with-esp8266-to-read-write-and-delete-data-on-16x2-lcd-display/
Tutorial 3: ESP8266 NodeMCU Web Server using LittleFS (Flash File System)----https://microdigisoft.com/esp8266-nodemcu-web-server-using-littlefs-flash-file-system/
Tutorial 4: ESP8266 SPIFFS (SPI Flash File System) with Arduino IDE---https://microdigisoft.com/esp8266-spiffs-spi-flash-file-system-with-arduino-ide/
Tutorial 5: ESP8266(NodeMCU)-BME280 Sensor on Web Server using SPIFFS---https://microdigisoft.com/esp8266nodemcu-bme280-sensor-on-web-server-using-spiffs/
Tutorial 6: ESP8266 save data permanently using Preferences library----https://microdigisoft.com/esp8266-save-data-permanently-using-preferences-library/