A draggable Truesize Leaflet map of the Brazilian states, and how to do the same for your own country or region

The good news is that using Leaflet Truesize plugin, you can add your own customized draggable polygons to the map. A map that I thought almost immediately is the representation of the draggable Brazilian states, so you could compare them to each other and to the size of other countries. And that is why this is used as an example for this tutorial.

How to generate a Leaflet.js webmap on QGIS with qgis2web plugin, and how to adjust some fundamental features on the map directly on html and JavaScript

Leaflet maps can definitely be generated from scratch. Many people and companies do that. But, because I am a QGIS enthusiast and many of my maps are already on QGIS projects, I can get the best of both worlds. I generate my basic map using as many specifications available on qgis2web as possible, and then, edit the html and the JavaScript generated by the plugin to adjust the map to my needs.