hi !!! I just got a new macbook pro and i can't figure out why i am not able to text anyone who doesn't have an iphone

This feature is supported through YOUR iPhone, under certain conditions. The messages are LITERALLY forwarded through your iPhone. If you do not have an iPhone using the same Apple-ID as your Mac, this features in not supported AT ALL.

To be successful, your iPhone must be set for SMS message forwarding:

Settings > messages > Text message forwarding = ON-- for the specific Mac you want to forward from

AND: your iPhone must working, be powered on, and within range of a cell tower.

How to forward SMS/MMS text messages from your iPhone to your iPad, iPod touch or Mac

To text non-Apple users from your Mac, you need an iPhone:

How to forward SMS/MMS text messages from your iPhone to your iPad, iPod touch or Mac - Apple Support

You don't. Messages is not a texting service, it uses the internet not the phone service.

https://www.indiatoday.in/information/story/imessages-vs-text-messages-know-the-difference-1840009-2021-08-12