Certain shipping methods are either incompatible with your business, painfully slow, or too expensive to use. By default SKULabs only disables Library Mail and Media Mail.
How to disable or hide a shipping method
Only active shipping methods are used in the Least expensive calculation default shipping option and appear in the shipping method dropdown. To remove a method:
Go to Settings > Shipping > Enabled methods.
Uncheck the box in the Active column next to each method you want to exclude.
Click Save.
To turn a method back on, check its Active box again and click Save. A disabled method can still show in the rates window, marked as disabled, with a tooltip that points back to this page.
The Enabled methods table. A checked Active box means the method is enabled; uncheck it to disable the method.