Whether your piece of music is a composition, or a signature tune, or background music in a film, or music to an advertising jingle it is treated in exactly the same way by IMRO. A payment is made to you for the use of this music on radio or TV.
Specifically with regard to advertising jingles any writer getting involved in this side of the music business should ensure that the ad agency they are dealing with submits to radio and TV the correct music details. Usually an ad agency submits information about the product name, the music title used, the composer and the duration of the piece of music used in the advert. Please ensure with any of your dealings with ad agencies that you are 100% sure they have credited you correctly.