In My receipt page(UI) how we can add condition at Submit Button level

Summary:

Hello Experts,

We have requirement in my Receipt page, attachment should be mandatory.

Even I am able to create the attachment mandatory but still I can click submit the receipt without adding the attachment.

I have tried to add some condition at submit button level but submit level all option showing disable

Please suggest how I can add the condition at Submit Button level.

For more detail ,Please find the attached document.

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