Personal effects
Personal effects are belongings left in the car you are shipping. Most auto transport contracts limit them or forbid them. They are not the same thing as cargo insurance on the vehicle itself.
Personal effects are anything in the car that is not the car: clothes, tools, a child seat, documents, electronics. Auto transport contracts commonly ban them or cap them, because the carrier priced a vehicle, not a moving van. Loose items become projectiles. A roof box changes the height. A trunk full of household goods can look like a different kind of shipment.
What to do before pickup
Read the personal-items line in the contract. Take out what it forbids. If it allows a small amount, list it, photograph it, and do not expect the cargo policy on the car to pay for it. Policies commonly exclude contents. There is no single federal packing list for a car on an auto-transport trailer. If the job is actually a household-goods move, with packing and a home inventory, that is 49 CFR part 375, and it is a different contract.
How this differs from cargo insurance
Cargo insurance, when the contract provides it, is about the vehicle. A scratch on a suitcase is not that claim. RideShipper does not insure the car or anything in it. If you need household goods moved, hire that service separately and keep the car empty.