Hi @jon00320 ,
Could you please share a bit more about your scenario?
Do you want to retrieve data using an external API within PowerApps app?
Based on the needs that you mentioned, I think Custom connector could achieve your needs. On your side, you could consider create a custom connector based on your external API, then within the Security tab, select API Key as authentication way, and specify the Parameter name to "Authorization", Parameter location to "Header":


After that, define proper action under Definition tab based on the action path from your external API. Then save your custom connector, within the "Test" tab, create a connection to the custom connector, it would show up a dialog asking you to provide API Key value (Access Token value), there you should type the following format Access Token value:
Bearer xxxxxxxxxx
then test the operation defined in your custom connector under the "Test" tab, check if it could retrieve proper records from your API.
After that, you could use the Custom connector within your canvas app to retrieve values from your external API.
More details about creating a custom connector in PowerApps, please check the following article:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/register-custom-api
https://www.youtube.com/watch?v=dBCS1nPsDiE
Best regards,