I have raised a bill from a cis contactor with both labour and materials but on the monthly cis return only the labour is showing. why?

Hello there, @imcoate9999.

Let's make sure to select the CIS materials under the Item Details in the Bill page. This way, it'll show the amount under the Cost of Materials column in your CIS return. 

To learn more about CIS in QuickBooks Online (QBO), I've added this article for reference: 

CIS in QuickBooks.

I've also added this article that can help guide you on how to record customer payments for products or services.

Feel free to leave a comment below if you have other questions. I'm always here to help.