I've just had to provide an "evidence of trading activity" report to the Department Of Work And Pensions (for boring reasons I won't go into). Generally the required evidence is geared towards businesses such as shops with weekly accounts; it's very different for a writer because it takes c.12 months to write a novel, then further time for sales to begin, so providing reports over a period of a few weeks may not show lots of units shifted! Still, this request (which feels like "Justify yourself!") is a good way of making me look at my activity recently. What have I done?
Obviously, some writing. Or, in many cases, research and planning preparatory to writing. When I have a pile of notes for a story I have to sort them out before I can start writing: make decisions, and get rid of contradictory ideas written at different times. That way I can be clear about what I need to write to fit into a cohesive whole. So the writing and planning done could be potential evidence.
Because of where I am - still doing publicity for one work while planning the next - it means I've been doing lots of marketing work in order to drum up reviews, sales and interest. This is just a selection of what I've done, in a random order, but it gives you a flavour of this kind of task. Any item in the list will have taken a lot longer to do than to write out as a bullet point!