It must be converted into RMB, and the amount of US dollars should be written in the remarks.

There is no need to open a special VAT invoice for export. The amount is dollars, not RMB. If you want to open it casually, you can't. The conditions for issuing export invoices are as follows. You must pay with a public account. If you pay in US dollars, you can only invoice in US dollars, and if you pay in RMB, you can only invoice in RMB. The amount on the invoice is the amount you paid.

If the factory cooperates with a foreign trade company, just issue him a VAT invoice. The rest of the tax refund is a company matter. Just follow the normal process of domestic trade.