1) OperationalError at /admin/csv_app/invoicefile/add/
no such table: csv_app_invoicefile
==>solve this error by cmd
makemigrations csv_app
migrate

2)System check identified no issues (0 silenced).
You have 6 unapplied migration(s). Your project may not work properly until you
apply the migrations for app(s): csv_app.
Run ‘python manage.py migrate’ to apply them.
July 13, 2021 – 14:55:01
Django version 3.2.5, using settings ‘proj3.settings’
Starting development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.

==>to fix this error, go to cmd enter:
$python manage.py makemigrations csv_app
$python manage.py migrate
$py manage.py runserver

3)os.path.join(BASE_DIR, ‘static’),
NameError: name ‘os’ is not defined
==>add this line in settings.py
import os