The 4 Major labels are: Warner Music Group, EMI, Sony Music, and Universal Music Group. Major labels seek artists that have an already large and thriving fan base, or a new act that could be very successful. When a major label deal is signed the artists them selves have to do very little work other than make music as there are so many people from the large groups that take care of most things: marketing, publishing, distribution, sales, advertising, legal, shipping and merchandising. They offer these services so they can take a larger cut of the profits however they are usually willing to give you a larger sum of money to record your album. Negotiating a deal with a major label is often quite complicated because of the many services offered. A record label is also a publishing company that manages things like brands and trademarks; coordinates the production, manufacture, distribution, marketing, promotion, and enforcement of copyright for recordings and music videos; conducts talent scouting and development of new artists and maintains contracts with recording artists and their managers. Whereas with an independent label you have to do a lot of that yourself or pay other people from outside companies to do such things. (the reason independent labels take a smaller cut).
A&R (Artist and Development) are a division of a record label who are responsible for talent scouting and overseeing the artistic development of recording artists and/or songwriters. A&R oversee everything to do with the artist up until the album release. Copyright protects original works whether that is a piece of music or a book. It allows an original work to be thought as owned by the creator. The relevant UK law is the Copyright, Designs and Patents Act 1988. When a song or piece of music is written, the person who wrote it owns the copyright and therefore has the right to decide how and when it should be played.