I would like to add the option of downloading a master file/template to my Shiny app (to be deployed in shiny io) as done in this app: https://ohri.shinyapps.io/Forecast/
Any advice on how to go about this or other examples of apps with this function would be truly appreciated!
The downloadHandler() output function is what you need. Its help page has an example. To create the Excel file, you could use the xlsx or openxlsx package. Alternatively, you could save the data in a .csv file; the default program for that extension on Windows is Excel.