i cant send or receive text messages with my iphone 12pro max.

Hi TiggerRhi

Welcome to the Apple Community.

Re: cant send or receive messages from android phones

In the Messages app:

Messages normally appear in blue bubbles, using wi-fi for Apple devices

Texts to Android devices appear in green bubbles and are sent using SMS / MMS (if turned on & plan permits )

To turn on : Go to Settings > Cellular >

NB: If Wi-Fi is unavailable, iMessages will also be sent over cellular data. Cellular data rates might apply.

Apple support's article:

What is the difference between iMessage and SMS/MMS? - Apple Support

says:

To use SMS/MMS on an iPhone, you need a text-messaging plan. Contact your wireless carrier for more information

You. might need to check how things are set up on your iPhone 12 Pro Max:

How to: Use Messages on your iPhone or iPad - Apple Support

And

What to do: If you can't send or receive messages on your iPhone or iPad - Apple Support

All the best :-)