Welcome to the Community, @kesukas123.
I'm happy you find QuickBooks Self-Employed (QBSE) right for your business. And yes, you should keep your receipts for recording purposes. Receipts are proof of your business expenses.
Here's how to add receipts in your QBSE:
- Go to the Transactions menu.
- Double click the transaction you want to attach the receipt to.

- Click browse from the Receipt section.
- Choose your image receipt and select Open to upload it.
- Then click Save.
Here's an article you can read for more details: Manually add transactions in QuickBooks Self-Employed.
I'm also adding this article for additional reference in managing your receipts in QBSE: Should I keep my receipts in QuickBooks?
Also, you might want to check this article that can guide you on how to get receipts from your email: Forward receipts to QuickBooks Self-Employed.
Know that you're always welcome to get back to me whenever you have other concerns and questions. I'm always here to help you anytime. Keep safe and take care!