In the picture you can see sketched profiles. They are all 2D sketches.
Than we activate a loft feature and a property manager opens on our left side.
Start selecting profiles in a way that they form a circular body.
If I decide to close this loft by selecting the firs profile, all I do is deselecting it.
In order to do this, we must select all our profiles again.
Than in the property manager there is a check box saying close loft. We check it and we can see the preview.
Click OK and we have our loft closed.