Click closed corner sheet metal toolbar or insert sheet metal closed corner.
Solidworks sheet metal overlap.
Click edge flange sheet metal toolbar or insert sheet metal edge flange.
Stop putting a small flat section on your part just to get it to convert to sheet metal.
The closed corner feature adds material between sheet metal features and includes the following capabilities.
If matching faces are not found you can manually select the faces to extend and faces to match.
Under flange length from the length end condition list select up to edge and merge.
Flatten it by converting it using the insert bends command instead.
Close multiple corners simultaneously by selecting the faces for all of the corners that you want to close.
The solidworks software attempts to find the faces to match.
In the edge flange propertymanager under flange parameters for edge for one of the sheet metal bodies you want to merge select an edge to use for the merge.