In order to turn on the SSH/Shell Access icon in the users' cPanel you should log in to the VPS WHM.
Navigate to Packages->Feature Manager. Create a new list or edit an existing one and make sure you enable theSSH Connection Window option. Click on the Save button to keep the changes.
You need to assign this feature list to all accounts which you want to have the SSH/Shell Access icon visible in cPanel.
More information on how to enable SSH access for your users can be found in our article here:
How to enable SSH on VPS through WHM?
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