Let me guide you on how you can view the list of categories in QuickBooks Self-employed, KellyTips.

You'll have to select the type of transaction for your categories to show up in all the category lists. I've added a screenshot for reference. Also, please know that the screenshots provided may be in the US version, however, they work just the same way as the UK version:

Once you've selected the type, you can click the category so you'll be able to view the list. I've highlighted the category in yellow.

To learn more about the most common allowable expenses that you can claim against your income tax, check out this article for more details: Allowable And Disallowable Expenses Explained.

Furthermore, to make sure to keep up your transactions, you can run reports so you'll know the different aspects of your business. You'll only have to customise them to make sure you'll get the data you need. Go through this article for your guide: Customise Reports In QuickBooks Online.

Drop a comment below if you need further assistance with categories. I'll be here to help you.