How do I erase a tab

I have been making some boxes from 3mm MDF and the courners have a support to fit the Lids onto. I want to remove the one Tab. I have looked for an Eraser to rub out the line after which I would Join a line But have been unable to work out how to remove the tab’’ Assistance will be greatly appreciated

For that one you can use the Trim Shapes tool.

To assist in finding more about the Trim tool: