For adding Users in your G suite first of all you need to have G suite account. If you have G suite account and if you are admin of that account than you are able or you can add or create users for your domain.
For creating or managing users you must have an admin account who are managing all the services of your domain. If you are an admin of your domain then you can do anything you want for your G suite. With admin account you can show your users activity, manage users, create users and so on.
Here are some steps for adding users in G suite :
Step 1 : Go to your domain admin console at admin.google.com. Also you can select it from your Gmail id by clicking setting options from there you need to select Manage this domain.
Step 2 : In your admin console, click on Users for starting creating users.
Step 3 : from there you can add two types of users like Single user and multiple users.
Step 4 : by clicking on create new user provide users details and it’s mandatory.
Step 5 : after clicking on create user you can see some details of users so take a printout or take screenshot of that details and provide that details to your user.
Step 6 : Now your user is able to use their G suite account.