web user interface with python

Im working on a project in python. Right now i wrote a few lines of code that can ask the user for a recipe and then put the recipe that the user wrote in a txt file. the program also can convert the recipe. for example if one recipe can make 20 cookies and the user wants 40 cookies the program will multiply each ingredient by 2. now i want to make my program more easy to use for other people in my life. I want to build a simple web user interface (so that other people that i know can use it on there phones). the problem is that i dont know how can i save the recipe that the user gave me for example on there phone on a text file and display the convert recipe to the user on the web.