Hi accounts65
QuickBooks online doesn't directly support corporation tax. You can set up a liability account, after calculating the corporation tax due from the previous years profit and loss, you can use a journal entry to transfer the amount due from the retained earnings to the liability account and when you pay the amount create an expense selecting the liability account in the category section.
We must make you aware that we are not trained accountants and that we recommend you qualify our information with an accountant.