No one can access your Bridge account unless you let them.
However, if you accountant has access to your Xero account, and you send invoices across - they will be able to see these. This will make tax time a lot easier for you and them!
If you send you invoices from Bridge across to Xero regularly, then you will always be up to date and have a happy accountant.
Any other questions, get in touch on live chat or call 1300 550 711.