We use you to talk about people in general including the speaker and the hearer:
You can buy this book anywhere > This book is on sale everywhere.
You can’t park here > Parking is not allowed here.
They don’t let you smoke in here > No smoking here
We use they or them to talk about people in general:
They serve good food here.
Ask them for a cheaper ticket.
… especially about the government and the authorities:
They don’t let you smoke in here.
They are going to increase taxes.
They are building a new motorway.
They say it’s going to rain tomorrow.