Universal credit want mine and partners total earnings from work in the last 12 months

[Theirmumxx]

It says use wage slips or bank statements. Will this be earnings before tax that they want?

I’ve only just submitted my claim and this is my first to do.

They need this information becuase it's relevant to how the benefit works - for example whether the benefit cap applies. If payslips are what they want then both gross AND net should be shown.