Services that renew on the same day, and are hence billed on the same day, automatically appear on the same invoice.
In the case of adding multiple services as an admin to a client account, you have the option when adding the service under "Invoice Method" to add the line item to an existing invoice, if there are any open invoices. If there are no open invoices you can choose to create an invoice, or not create an invoice when adding the service.
So for the 1st service, I'd select "Create Invoice", the default option. Then, on subsequent services you may choose to add it to this existing invoice.