The pitch angle for a 90° transmission is easy. it's something like arctan(z1 / z2) where z1 is the number of teeth of the first gear and z2 is the number of teeth of the second gear. For any other "transmission angle" you can use the sketcher to find out.do you know I can retrieve the pitch angle value?
set alpha to (90 - pressure angle). In your case this would be 90 - 20 = 70. I have corrected this and renamed "alpha" to "pressure angle". If you download or pull from github  this will be updated.what I see is the different form of the teeth, How can adjust/change it?
What is exactly meant with the tilt?the other think is the tilt, how can adjust/modify/change the tilt on top and down of the teeth?
There are several different tooth-profiles for bevel-gears. My bevel-gear is made from spherical involute profiles. Cutted gears often have octoid tooth shape. I think some cad-tools also use an equivalent cylindric involute.Could be possible to have different profile of the teeth (Gleason and other, I don't know if others exist)?
Use the "Part Design" workbench to make the base geometry. Take a look at the example quick61 showed some posts before. There are also many tutorials on youtube how to use the "Part Design" features. So you simple create the a revolved sketch without the teeth. For the sketch use the z-x or y-z Plane because the gear created from the bevelgear button will allways be aligned in z-direction. The "center point" of the gear is allways the origin.regarding the tilt , see the attachment image
As far as I know spherical involute is quite good for bevel gears. There exists other forms because the cutting machines often can't produce the spherical involute exactly. But I think it doesn't make much sense to introduce other profiles for bevel-gears. What's the reason for the need of this special tooth profile?sorry the the gleason is a system that regard high perform catch gear and not really the tooth profile instead coming in deep on the tooth profile in attachment an image for a product that I concern in my project, could be possible have also this type of tooth profile?
The example I have made isn't fully parametric. So you can't only change the parameters to get the gears you are looking for. You have to correct every step... So it's better to create it from scratch.great example file, the last question is if with your example file I can create a bevel gear like as we can see in the image attached.
I based my project on this type....inside the image there are some italian word sorry you not consider.