Entering external invoices

Dear Sir/Madam,

I am a nurse working as a self-employed person in my secondary occupation. I sometimes invoice directly to an organisation where I have carried out an assignment. However, I also work via an assignment platform. They then invoice the customer on my behalf, under my name, and send an invoice to me with the service charges.

My question is: how do I record the income from the invoices they have issued as income? Because this sometimes covers several days. Do I need to split the invoice into daily income?

I saw under ‘Income’ that you can also upload an invoice; is this how it should be done?

Kind regards, Céline