How to Add a User and Grant Root Privileges on CentOS 7

Step 1: Add the User

It’s just one simple command to add a user. In this case, we’re adding a user called mynewuser :
adduser mynewuser
Now set the password for the new user:
passwd mynewuser

Step 2: Grant Root Privileges to the User

For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor
visudo
Find the following code:
## Allow root to run any commands anywhere
root ALL=(ALL) ALL
In this case, we’re granting root privileges to the user mynewuser . Add the following below that code:
mynewuser ALL=(ALL) ALL
Then exit and save the file with the command :wq .
If you’ve followed the instruction above correctly, then you should now have a user setup by the name of mynewuser which can use sudo to run commands as root!