Personal emoji

There are Emoji/Memoji style apps in the iOS App Store that use can use that even include a special Emoji/Memoji keyboard for their apps that can be used in emails and the Messages app.

Just look in the app store the Emoji/Memoji apps.

My Emoji/Memoji that I use here in these Apple product support communities was mostly created with apps

Emoji Me and modified using Pixelmator for iOS.

Good Luck to You!

For animoji's see this link

https://support.apple.com/en-us/HT208190

emoji's are managed by Unicode.

www.unicode.org

if you need an emoji made up there is a submission procedure, but that does not guarantee they will make it.