I have read the popular blog post https://www.stevejgordon.co.uk/introduction-to-httpclientfactory-aspnetcore on using HttpClientFactory
To quote from it
Thanks for replies.
So it is possible to use in console app.
There are a few ways to do this, depending on what way you want to go. Here are 2:
Directly add to ServiceCollection e.g. services.AddHttpClient()
Use Generic host e.g. Add httpclientFactory in .ConfigureServices() method
See here for blog post using in console app