We recommend using a platform that you and the participants are familiar with, and one that means you can have a call for an hour or more. You could use Skype, Zoom Premium, Microsoft Teams, a group video call on Facebook Messenger, etc. (Free Zoom accounts only allow 40 mins, but there are a couple of points in the game where people could join a new call link to give you more time.)
The host will need to be on a computer or laptop, and we’ve found the game experience for players is far better on a laptop or computer because they will need to use the chat function, open documents and visit websites while working together. Using a tablet to play is possible if people are comfortable jumping between screens, but mobile is more difficult.
As long as someone can join an online video call and use the chat function, they should be able to play. Many of the activities involve following links in the chat to written documents they will need to look at.
If you have someone in the group who feels less confident, nominate someone to share their screen, so everyone can watch and help solve the puzzles without needing to follow links or open documents.