Goto the folder where the database is and then
sqlite3 db.sqlite3
Then
.tables
or
.schema
depending on what you want. Instead of invoking sqlite3 directly you could do
python manage.py dbshell
and then type the sqlite commands.
If you are working with a legacy database you can generate Django models for that using the
python manage.py inspectdb
please see https://docs.djangoproject.com/en/3.0/ref/django-admin/#django-admin-inspectdb for additional info.
But please do yourself a favour and get a GUI database client. Life is much easier when you have one.