I'd need some help in understanding what I need to do, admittedly I am getting into this for the first time. I am full-time employed in a privately held company in the UK. Recently, I started doing some work (in the 'spare' time, e.g. evenings and weekends) to help my girlfriend out with some things she would not know how to do. My original idea was just to help out, but now her company wants to pay me for my work and asked me whether I can 'invoice'.
I have been checking the HMR website for advice, but could not find anything. My questions are, and apologies for them being so trivial: - what exactly means 'invoicing'? - what does it involve? - Can I 'invoice' while a full-time employee at a company? - Supposing the above is possible, what would I need to do?
Sorry for the many questions, and thanks in advance for your help.