Songwriters compose music and write lyrics for songs. Some songwriters are also referred to as composers if they compose original music, particularly for film scoring and classical music creation
Not all songwriters work on both lyrics and music; some have a focus on preference on one above the other. In these cases, they'll often pair up with other writers or producers.
Many of today's songwriters are also producers, as more accessible technologies have enabled them to create high-quality output from within a regular laptop or desktop computer setup.
Some songwriters are retained as staff writers by record labels or music publishers; some have deals where they agree to deliver a certain quantity of songs within a time period; and others work on a freelance basis.