RCS is standard with almost all Android devices. Apple will support RCS only if the carrier built out the backend for RCS. This means that there might be a carrier or two that won’t support RCS. RCS has an advantage of using data to communicate. This means full resolution images, longer messages, and the transmission of RCS is free everywhere in the world as long as you have data services. This means I can send an RCS message to someone on the other side of the world, and it won’t cost either of us anything (except data). An image varies, but it would take 1,000 characters to use 1kb of data. 1,000kb = 1MB. 1,000MB = 1GB. This should give you an idea of how much data RCS actually uses, and might be worth it when compared to SMS. Android devices automatically sends RCS if you are using Google Messages. My number is +1 4126829751.