If you would like to post your Link My Books subscription fee invoices to Xero, please navigate to the billing page, click the invoice tab and you should see this screen.
Toggle on Automatically send new invoices to Xero
Select the Xero Account to send invoices to
Select an Optional Start Date, then click Save Settings
If no start date is selected then only future Link My Books invoices will be auto-posted to Xero for you.
Please note that if you have already manually sent these invoices to Xero, backdating auto-post will duplicate them.