You will need to notate your music at some point, if you want it played by others, especially trained professionals. There are many software programs, at various levels of components and price, that will assist you. But you will often audiate - hear things in your head that you wish to use in your composition - but again, better write those down before they evaporate! Audition also means the ability see see printed music, and without actually playing it n any instrument, HEAR it in your head. Think of the X and O patterns a football coach draws - he and the players see PEOPLE at those positions. Many people will write down something simple and linear, and say they *composed*; The true art of composition is learning how to develop your materials - both expanding and pruning, so that you get the best possible outcome.The more music theory you know, up to a point ( you really do not need to super arcane stuff) the better off you will be.
Yeah, we all know the stories about the old composers with limited skills. Their talent far outweighed their shortcomings in technique. But if you intend to have others play your music, or ever get anything published - learn to read music and get decent piano skills. Not concert level - just functional. Are there people TODAY who are short on legitimate writing skills? Sure - but then have technology/software and other people who know how to run it, who will take care of that. And for public consumption of POPULAR - great looks and an outrageous personality beats musical talent every day, it seems.