The whole legal side of registration, title, road tax, insurance and ownership is just so different in different countries. Even different states in the good ole' US.
In Great Britain and N Ireland, we have one unified system. The DVLA holds registration and ownership details for every vehicle on UK roads. The registration and number plate are transferred when you sell the vehicle, so a vehicle has the same registration number/plate from new till it is scrapped. Except when an owner wishes to transfer a 'treasured number' onto a vehicle - like my Kawasaki W800. Issues about title and ownership are something most people would never encounter. Unless you import your own vehicle privately or seek to buy cheap from some really dodgy individual you will never worry as long as the seller has the DVLA document. And they generally do.
Road tax varies on class of vehicle. For a small bike it's £21 per annum, rising to £96 for bikes over 600cc. For cars, road tax is calculated on a formula based on the amount of CO2 it produces per mile, but they haven't applied that thinking to bikes yet. The Good News on road tax is that a vehicle over 40 years old can be registered as 'historic' - you still have to buy road tax every year but it costs nowt and there are no restrictions on how you use the vehicle. My XS comes under that rule so road tax is free with no mileage restrictions or other nonsense.
Insurance you have to arrange separately with a private company. Insurance is compulsory and they check you have it when you pay road tax. Cheapest is 3rd party, which only covers losses you might cause to other people, or you can pay more to cover loss of your bike by fire or theft, or fully comprehensive which pays out for all losses you face, for example if you fall off and damage the bike.
Some companies offer a single insurance policy to cover all the bikes you own and this usually works out a lot cheaper. I paid £178 for twelve months to insure three bikes, fully comprehensive and with an agreed replacement value on the XS650.
The other legal issue in the UK is that vehicles over three years old - except historic vehicles - have to pass the MOT test, an annual inspection which you have to pay for - they check a list of safety points such as tyres, wheel bearings, brakes, brake lights, frame straightness and integrity. Oh, and the horn must work. Most people would probably agree that the MOT test is a good thing, unless they just failed one of course . . .