iMessage is the best messaging app ever, it works only between phones and makes the texting and messaging experience awesome.
If you are an iPhone user you will be able to text and send pictures and videos and audio messages for free all over the world with iMessage.
iMessage is developed by apple and is fully encrypted, no one will ban you and you own your conversations.
Be aware that if you are doing something illegal you will be able to be traced and better solutions like Session are recommended.
iMessage is free and can be used only by iPhone users, just by typing the number or email of the user if the bubble turns blue you know that the other user has an iPhone and you can send free messages, meanwhile, green bumble means the other user has no iPhone.
You will need a free iCloud account to access all its features and many models and adult performers are using it to interact with their fans.