Edit: NOTE, I am the receiver of the texts.
So many people asking me to have my wife do something different on her end.
Beloved, she is on iPhone because she doesn’t want to do anything “weird.” She is texting from her phone number using her texting app. That’s what’s going to happen.
Now, why can’t I get iMessage on my android phone? If it’s just a messenger app why not make it available for Android?
I’d use it.
If you mean changing which app natively gets used for texting, that’s not something you can do on iOS. You can choose to open a different app, but if I tell Siri to text someone it will always 100% without a doubt no way to circumvent it use the standard Messages app. iOS doesn’t let you change your default for texts.
Hell, they only allow you to change your default web browser because they were dragged into court kicking and screaming. And even then, all third-party browsers are forced to use Safari’s engine for the backend, and aren’t allowed to use their own engines. Even Chrome, Firefox, and Brave are just reskins of Safari on iOS. And even then, any apps that open an in-app browser will still use Safari even when your default browser is different. For instance, I’m browsing lemmy on Voyager, and it opens all links in a built in Safari browser, (even though my default browser is set to Firefox.)