There are innumerable designs for tools to hold screws in place until you can get them started but the one I seem to use the most is one of my own design. I call it a garrotte for obvious reasons and it's simple to fabricate in the home shop.
Mine consists of a loop of waxed, heavy-duty thread pulled through a length of 1/8" OD brass tubing.
A wire passing through the loop and anchored to the end of the tube prevents the garrotte loop from being pulled back into the tube when the ends projecting from the other end of the tube are pulled.
In use, it's looped around the screw to be positioned...
and pulled tight, thus trapping the screw.
The screw is still free to rotate about its axis. The tube is then used to position the screw while a driver seats it into whatever receives the screw.
Takes about ten minutes to make and that includes waxing the thread.
I discovered it has a secondary use. Until they perfect non-ferrous magnets, it makes a pretty good lasso for snaring small items dropped into finger-inaccessible holes.