Yes, you can send the invoice and contract separately!
The easiest way to do this is to go to Client tab > Docs.
There, you will be able to download the pdf version of the invoice and contract separately and send them to your client via BOS's built-in email system or your preferred email client.
You can go to your Client Portal for an event quicker access to both documents! Just go to Client tab > Client Portal, and you will find the most up-to-date invoice and contract. Since each event generates its own Client Portal link, you can simply copy the browser link of the Client Portal you are trying to access and email/text it to your client.