If i make sales invoice it shows in trial balance in another customer, why

Hi @o-damer, 

Thanks for asking as here in the Community. It could be that you're creating an invoice for a sub-customer. That is why it shows a different customer in the report. The customer shows in the trial balance report could be the parent customer. 

I'd suggest you check the actual sales invoice to verify the associated customer. 

For future reference, read through this article in case you'll need both the parent's and sub customers' charges to appear on the same invoice: What does the bill with parent feature let you do on invoices?. 

Let me know if you have further questions, @o-damer. I'd be here to help.