How can I turn off the marked area?

[ercument]

Hello good day.
How can I turn off the marked area?
Thanks in advance.

[mihai.s]

What do you mean by ‘turn off’? The circled area shows that there is missing surface there.

[ercument]

I want to create a surface

[mihai.s]

Use Line tool and Ctrl + Eraser tool to smooth the edges.

[ercument]

thank you very much