When you wan to to add revenue / category in the revenue / customer view.
Choose customer "0". This way its possible to add revenue on different categories without specifying customer. If you never want to use the account to input revenue / customer, change config to use the account in the view "other revenue" instead. See guide below
When the account is missing
If you are missing an account in the Other revenue / OPEX / CAPEX app, go to admin and then to the dimension editor. Then click on the dimension Account and select a value in "Show in views" to decide in which tab you want the account to be displayed.