OK, you don't say what Windows or Avast versions you are talking about.
Avast is a resident, on-access antivirus and part of its scanning modules uses an internet connection to check out unknown files, etc.
Avast also really does require Internet access to be able to keep the Virus Definitions up to date or it too could be as much use as a chocolate teapot. Or it will keep stating that your Virus definitions, etc. are out of date, that would require you to periodically download the full virus definitions database (from another PC with internet access).
Some time ago there used to be a registration for old versions of Avast, but I don't know if this still works,
https://www.avast.com/registration-free-antivirus .
As for screenshots, Attachments and other options (below the text input window), click to expand.