There are three types of insurance you should have:
- van insurance to cover you to use your van to carry goods for 'hire and reward' — this can be courier insurance or light haulage insurance depending on the type of work you do. this type of insurance, often called road risks insurance is a legal requirement.
- goods in transit (GIT) insurance to cover the goods you are carrying. this is not a legal requirement but often required by businesses you do work for
You should also have public liability insurance, but you probably don't need employer's liability.