I extracted with QGIS a municipality from a state map, then divided it with a grid. I don't want the borders of the grid features to be seen so I changed the color of the map and the color of the borders to be the same, then I saved it as a new file (not a new project). Does anyone know why when I open it again it does not save the changes? (the divisions of the grid are visible and the color settings I saved are gone).
QGIS does not store the style in the layer data itself because it handles different formats so that would be hard. Styles are stored in the project file or in a qml file.
To export the QML file. Open the Layer Properties and select the Save Properties button.
Tip: If you name the qml file the same as the vector file it will auto style when you open it.