1) From within the drawing, you might need to navigate in the part feature tree under the drawing view and find the sketch and hide it there.
Or if you don't want any sketches shown on the drawing you can go to the View menu and deselect Sketches.
2) In the drawing document properties under Line Font, choose "Tangent Edges" and set it to Solid and set the thickness you want. You can see what your normal line thickness is by selecting "Visible Edges" so you can make sure you set the tangent edges to a thinner line. If necessary you can pick custom line thickness and type it in.
Then in the drawing view set tangent edge display to "Tangent Edges With Font".
If you are always going to want the tangent edges this way then you should make the line thickness change in the drawing template, and then in your system settings under Drawings > Display Style set the Tangent edges setting to "Use font".
3) Right click in the view that you want to be free and select Alignment > Break Alignment.
Thank you for so detailed answer, especially the second one.
The fist part was clear but the necessity of applying the setting (Use Font) is quite special.
The first question is not solved in this particular drawing but works well in others.
Seems like some model or drawing problem.
The drawing still keeps the sketch even in the case it was deleted in the model.
Make sure that you're hiding/deleting the correct sketch.
The sketch I deleted was correct in that particular drawing.
I am training so I could make some unnatural things and cannot blame the software.
I have repeated the drawing sketch visibility option on the new and other existing
parts and it works fine.