Create separate SFTP user for specific website / domain / folder

Hello to all EE staff and followers, My name is Anas and it’s my first day with EE :slightly_smiling_face:
I have successfully installed EE4 on digitalocean and shifted all my 5 websites. As I learned the websites are set up in a separate folder. I want to create a separate SFTP user for all websites / domains.
Someone please suggest how to do this.