Trackpad Drag Option - HELP ME

Please help me,

I can't use the drag option with my trackpad on Macbook Air (Early 2015).

I tried to active the option on trackpad setting but it doesn't exist.

I have also tried to find the option in the Accessibility and nothing.

Is it possible i cannot use the so common option of the trackpad?

It was very useful to drag windows, files ect...

Now I can only press with one finger and then drag windows.

Thank you