Equivalent Linux commands for Windows ones to create user and database

There is a manual for configuring PostgreSQL on Windows with these commands:

C:\"Program Files"\PostgreSQL\12\bin\createuser.exe --username=postgres --superuser --pwprompt saleor

C:\"Program Files"\PostgreSQL\12\bin\createdb.exe --username=postgres --owner=saleor saleor

I'm going to do the same on Linux, but I'm not sure how. I know that I have to do:

> sudo su postgres
> psql 

psql (13.3)
Type "help" for help.

postgres=#

But I'm not sure what to do next. I appreciate any help.