Hi,

First of all you have to create the user and then give the sudo privileges.

Here is the command to create user:

adduser roseindia

Here is the output of the command:

adduser roseindia
Adding user `roseindia' ...
Adding new group `roseindia' (1001) ...
Adding new user `roseindia' (1001) with group `roseindia' ...
Creating home directory `/home/roseindia' ...
Copying files from `/etc/skel' ...
Enter new UNIX password: 
Retype new UNIX password: 
passwd: password updated successfully
Changing the user information for roseindia
Enter the new value, or press ENTER for the default
    Full Name []: roseindia
    Room Number []: 
    Work Phone []: 
    Home Phone []: 
    Other []: 
Is the information correct? [Y/n] y

Now you can add the user to sudo group with following command:

usermod -aG sudo roseindia

Above command will add the user in the sudo group.

Thanks