A standard Steam account will allow you to have access to every game available, let you make purchases and join in discussions with the online communities. However, you can remove access to these features using the "Family Options" which can be activated on a child's account or a parent's account (this is a toggle-able setting that can be turned off depending on who is using the account at the time).
To enable Family View:
- Log into the Steam account your child will use.
- Click the Steam menu in the top menu bar.
- Open the Settings option.
- Go to the "Family" tab on the left side of the window that opens.
- Click “Family View” to start the Family View wizard.
- Step through the wizard to select the content and features you’d like to be accessible while in PIN-protected Family View.
- Select and confirm your new PIN.
In this mode, your child only has access to the content that you have selected.