How to add users to a group?

To add users to a group in Linux, you can use the usermod command. Here’s how to do it:

Open a terminal.
Use the following command to add a user to a group:
```
sudo usermod -aG groupname username
```
Replace groupname with the name of the group you want to add the user to, and username with the name of the user.

For example, to add a user named john to a group called sales, you would run:
```
sudo usermod -aG sales john
```
Verify the change by checking the groups the user belongs to:
```
groups username
```
For example:
```
groups john
```

This command will display all the groups that john is a member of, confirming that the user has been successfully added to the specified group.