How do I identify a 2.99 purchase from Apple?

This is primarily a user-to-user support forum; other Apple users like you. We don't have access to information about charges to your account. Apple has a support article about charges — see each of the steps in the following instructions. They include information on contacting Apple Support if the other steps don't help. See: If you see 'apple.com/bill' on your billing statement - Apple Support

Based on the amount, I'd guess that this is a charge for

• an iCloud+ storage plan
• a couple of songs purchased from the iTunes Store
• an app purchased from the App Store
• or something along those lines

We don't have access to your billing history, so you'll need to review your billing history (and/or e-mails that Apple sent you) to figure it out. See the Support link that FoxFifth provided.