Whosda La

Hi I need some advice I do food delivery for uber as self employed and sometime as I can subtitute the work I let my friend do the delivery.whatever he makes I get paid in my bank account and I transfer to his bank account without deduction.Also same for my friend he let me use their just eat account to do the delivery and whatever I make they transfer me to my account without the deduction and everything is written down.When I have to do the self assessment how do I declare that some of the earning was paid to a friend as I subtitute the work and I got proof I made the payment to him and give them his details as he is self employed and have to declare his earning and as I did some of the work he paid me into my account wich I will declare also.When I contacted HMRC they told there is nothing like that appart from the construction scheme when u need a subcontractor but I have to register as a director.So am lost. thanks