How to have local custom domains for local mail server through postfix?

I have postfix in rhel 7.7 and in system I have users such as root, james, peter etc. My FQDN of server is zwados.yutery.com and hostname is zwados. I need to send a mail from here from user [email protected] to [email protected]. Now how can I configure or create this domain gedyuyu.com which is just a domain in my machine zwados?

I am thinking in terms of hmail server in Windows where you can add domains in a Windows OS machine and then under that domain add users. You don't have to purchase domains in hmail server as they are locally viable.