Building Custom Emojis Like Classic Emojis

Hi community!

Hope I’m posting this in the right place. I followed Chris’s super quick tutorial for creating a sticker pack, and got that, but I was even more curious about creating custom emojis or stickers, that operate like classic apple emojis.

Meaning, my custom emojis would allow text to be written beside them or remain large if I send the emoji / sticker by itself.

Is this even possible? I’m definitely a newbie, and was looking for some guidance.