Log into Sumac as an Administrator. From your main console, go to Utilities > Customize Database > Preferences.
That opens the Preferences area where you set up the rules for how you want Sumac to behave for your organization. Click CRM on the console on the left and then click the "Contacts" tab. Click the Choose Tab Names button.
Here we find a table where we can not only hide tabs, as well as rename them. As an example, perhaps you do not track your constituents' Vacation Addresses, so you can click the "Hide" checkbox to hide the Vacation Address tab.
Click OK to save the change, and that tab will no longer appear when viewing contact records.