Simple option:
Download the tab-seperated-values (tsv) table from here

Harder option:
Download the (current) 2024 world hertiage sites list from the UNESCO website
Comes as a XLSX file, so convert this to a simple TSV file for processing
Create an english version (file has multiple languages) to reduce information and simplify (currently app is designed for english headers)

You can try automate the process as below in bash

  #Download
  wget https://whc.unesco.org/en/list/xlsx/whc-sites-2024.xlsx
  #Convert to XLSX to TSV
  #need xlsx2csv installed 'sudo apt install xlsx2csv'
  xlsx2csv -d '\t' whc-sites-2024.xlsx whc-sites-2024.tsv
  ##extract just the english parts
  ##and correct some formatting issues that seem to be a hand over from other formats
  cat whc-sites-2024.tsv | awk -F "\t" '{print $1"\t"$2"\t"$4"\t"$10"\t"$16"\t"$18"\t"$23"\t"$24"\t"$25"\t"$37"\t"$38"\t"$39"\t"$45"\t"$47"\t"$48}' | sed 's/<.*>//g' > whc-sites-2024.en.tsv

You can then open the table in tools such as microsoft excel/libreoffice calc/google sheets and fill in your column
Put your name at the top of the far right column then put 'Visited' if you have been to the corresponding UNESCO site in that row as below
Any additional person can put fill out a column to the right and so forth
You can then save this file/export it as a tsv (the original file format and common option for saving with above tools)

Now you need to run the app and import your table

Simple option:
Use the online version at hosted by shinyapps.io

Harder option:
Install R then run the shiny app locally
To do this launch the app project in R and run the app file

  ##in R
  library(shiny)
  ##then run the app putting the path to the app downloaded
  runApp(appDir = "UNESCO_app/")