How do I take ear tip fit test?

Hi JPhillip!

As far as I understand, you are taking about AirPods Pro's ear tip's. Try inserting the AirPods with the medium-sized ear tips in your ears so that the AirPods are seated comfortably and securely. If you can’t get a good seal, try adjusting the AirPod or switch to a larger ear tip. If the ear tip feels too large in your ear or is uncomfortable, try a smaller ear tip.

You can use the Ear Tip Fit Test if you're not sure that you're getting the best possible sound quality and noise cancellation. Choose a comfortable fit with a good seal.

1. With your AirPods Pro in your ears, go to Settings > Bluetooth on your iOS device. 
2. Tap the info button  next to your AirPods in the list of devices.
3. Tap Ear Tip Fit Test. If you don't see the Ear Tip Fit Test, make sure that you have iOS (or iPadOS) version 13.2 or later.
4. Tap Continue, then tap the Play button .

If the test suggests adjusting or trying a different ear tip, try adjusting your AirPods Pro and testing again. Then try a different size. You might need different sizes for your left and right ears.

How to remove and attach ear tips

To remove an ear tip, pull firmly with your fingers at the base of the ear tip, where the ear tip is attached to the AirPod.

To attach an ear tip, align the ear tip with the oval-shaped connector on the AirPod. With your fingers at the base of the ear tip, push the ear tip onto the connector until you hear it click into place.

I got all of these information from Apple's website, and also you can check there too.

>https://support.apple.com/en-us/HT210633

Hope that it helped, have a wonderful day!