Creating invoice for customer

I want to create an invoice for customer but in the Account field, it shows “Interest Received” or “Sales” where it should show Service.

Go to Settings, then Chart of Accounts and either create new income account called Services or rename Sales account to Services

Thanks Lubos , and my second query changing from Purchase order to Work Order.

What’s work order? Manager doesn’t have anything that is called “Work order”

when first party are allocated a work where material is supplied by second party and first party are there to install the material. in this case first party is given and paper document for performing that work. selling or purchasing is not done by first party.this is called “work order” or “service order”

OK, so customer (the second party) will give document called Work order to the supplier (the first party) who will perform the work. Isn’t the work order the same as sales order? Manager has Sales orders tab already.