To some extent it will depend on the quality you wish to achieve.

Cheap external USB stages are out there. I have used a cheap external SoundBlaster phono/ADC in the past. Maplin also did one though I have not checked if they are still open for business.

You can get cheap ADCs without phono stages but which can be connected to phono stages. For example I use the Novation 4X4 Audiohub.

Some of the phono stages by Project. Rega and NAD include ADCs though tend to be restricted to 16bit transfers only.

Software is relatively straight forward. Audacity is the obvious freeware option. Ocenaudio is another freeware option though I have not tried if for transfers.