There are multiple considerations you should take into account when mounting your smartphone on your motorcycle.
Here are two different mounts I use on my bikes. One is a dual sports bike (Suzuki DR), the other is a sport touring bike (BMW R1100S). Both have different handle bars and are mounted differently.
There are two types or smartphone mounts, either your smartphone is in a waterproof case, it is only held by a grip mechanism. The benefit of the waterproof case is that your phone is protected from water and dirt. On the other hand they might make it harder to read the screen and during a hot summer day smartphones tend to overheat. A smartphone that overheats can behave anywhere from funny to frustrating. My smartphone's GPS sensor turns wild when overheating and puts me anywhere on the map except for my actual position. If you buy a waterproof mount, check if there is an option to insert your charging cable into the case.
You will find a good overview of different motorcycle mounts on Amazon.
If your motorcycle has a pipe handlebar, like most other motorcycles, there is not much to discuss, just get one you like. If you got a stub handlebar, things get more complicated. A manufacturer called “Ram Mounts” is known for high quality mounts and offering a wide variety of mounting options, often using other bolts that are already added to your bike, have a look at the different Ram Mount Bases. If you cannot fit a Ram Mount Base on your motorcycle, like me, you can look for regular pipe handlebar mounts that are supposed to be fixed with cable ties. You have to add a piece of rubber between the mount and the handlebar bridge. On my BMW R1100S I had to got with the cable tie method as there is almost no other easy way. I attached a picture of my first approach, it became more sophisticated over time and I also clipped the cable ties ;).
I am aware that you can fix a bolt under the the handlebar bridge of the R1100S, but this makes the mounting quite complicated.
No worries, you can always put your phone in a tank bag. However, you should consider that you usually have to look further down to see the phone there. Therefore, it I recommend also having an audio link when using a tank bag, so you don't miss any turns. You can also use audio only to navigate, just connect your headphones and start the navigation. Enjoy your rides with Kurviger.