Automatic numbering of points during digitization in QGIS?
One method is to use a virtual field which would automatically number your points using the $id expression (or whatever expression you prefer):
Note that you will need to save a project file for this as virtual fields are saved in the .qgs file and not in the shapefile itself (but you can re-save the shapefile as a new one using the Save As... option which would convert the virtual field into a normal one).
I think you talk about the id of shapefiles, if so you can go to layer properties (doubleclick the layer) then go to fields and set the item that is called 'Bearbeitungselement' in german to UUID-Generator (id field type must be text) as shown in the screenshot below (https://en.wikipedia.org/wiki/Universally_unique_identifier).
When digitizing your points (or other geoemtries as well, of course) you get this:
and you will just have to enter the other attribute values if applicable.