Thanks for posting in the Community, @kkscreativeworks.
When adding receipts in QuickBooks Self-Employed (QBSE), they will show as pending for approximately 24 hours. The system searches for a possible match within your account using the date, description, and amount.
If it's unable to find one or there are multiple potential matches, you'll have to click on the Need Action alert in the Transactions tab to review them. This will create a new transaction to match receipts. After that, you can categorize them.
Just in case, I'll add these articles for future reference:
Please know that I'm only a few clicks away if you have any other concerns. I'll be here to answer them. Enjoy the rest of the day!