If the angle btw the incline and horizontal surface is increased what will happen the magnitude of force needed to hold the object at rest on the incline

The force needed will be greater to hold the object at rest.

Explanation:

For a better understanding let's take a look at the attached image.

In the image there is an example of this condition, we have an object of 3 kg-f mass, the first angle between the horizontal and the inclined plane is 35°. When we increase the angle to 45°. We can realize that we need to hold the object with a stronger force.

The calculation and the equations based on Newton's laws can be found in the attached image.