This is a foolish requirement.
The casino team are trying to just stress you, why can't they ask for your wallet address and put that in blockain scans and look into your past histories themselves? Some online casino requirements are crazy at times, if this is bank account requires it is different, but asking for your income statement that is publicly available on the blcokchain sound stupid.
Anyways, you don't have a choice than to give them what they want, use blockchair or any other and download the PDF, I am not sure that Electrum wallet has that feature.
It's indeed a strange requirement because I have never heard of any casino asking for such a document. However, it will depend on the information that the gambler gave to the casino during his registration. Some people might be receiving salaries with Bitcoin.
I also suspect that the customer might be having a dispute with the casino, so they need to see his transaction history. His history has questions about KYC and withheld wins.
The OP had not also made any comments or clarifications since he made the original post. It would have given us a tip about why the casino is requesting such information.