How do people do those symbols?

On IG I see like cloud symbols and heart symbols and really cool texting styles. And I can't figure out how to get those. I'm on my iPhone so I want it on my phone and not a computer. Does anyone know how I could do this? Please answer!

Unicode tables or charts.

Symbols:

http://unicode-table.com/en/sections/miscellaneous-symbols/
http://unicode-table.com/en/sections/dingbats/

Text:

http://unicode-table.com/en/sections/letterlike-symbols/
http://unicode-table.com/en/sections/greek-coptic/
http://unicode-table.com/en/sections/currency-symbols/
http://unicode-table.com/en/sections/cyrillic/

You have to individually copy and paste each character or symbol, you can keep a notepad app of symbols separated by spaces in alphabetical order to make it easier.

Some symbols will be displayed as multicolor emoji on Apple products.