I have a GeoJSON file which represents geographical polygons. Drag and drop to QGIS3 opens the file and I can see the polygons.
Each polygon has several properties identified by QGIS (Can see them via Layer Properties-> Fields)
Is there a way to display these fields (I only need one) on the map?
To Elaborate on Eriks comment: what you want is called a label.
Labelling is explained in the manual here: https://docs.qgis.org/3.16/en/docs/user_manual/working_with_vector/vector_properties.html#labels-properties .
You can label using fields in the source data or based on arbitrary complex expressions.
