This is a great place to store all of your accomplishments -- education, work history, volunteering, awards, workshops/conferences, publications, trades, skills development. Over time, it is hard to recall these things, so keeping them all in one place, in chronological order (grouped in to headings), becomes incredibly handy -- and an interesting walk down vocational memory lane when you need to pull out items relevant to a job being applied for. You, or a client, may recall skills and talents long disappeared years back, once again handy. Update this often to capture everything you've done. Make sure to write up the skills used and accomplishments in an active voice that speaks to facts and achievements -- self-promote in a factual way.
Over time, this general resume will become really long... pages and pages. When sculpting your specific resume for a particular job, you will have to use fine judgement and editing skills to pull out the right information that tells the right story about how you are fit for the job, and how your background has led you to that application. This becomes the process of creating job, company, and/or industry specific resumes.