How do i uninstall software from my mac book pro

Question

I installed canon software on  my mac, I would like to uninstall, it will not drag to trash can

Answer 1

Best way to uninstall programs or apps
The best way is to contact the developers site for uninstall instructions, especially if the software required you to enter your Admin password to install.
It might have placed "hooks" into the OS X kernel called kext files that load when OS X boots up or in other locations that require a uninstaller to use root level power to uninstall correctly.
If one simply only drags the application icon they see in their Applications or Utilities folder to the Trash, what happens is these leftover parts in OS X itself don't get updated for compatibility with later OS X updates and/or might cause a security or stability issue later on which the machine will boot to a "Gray Screen Issue" and remain stuck.
Self contained programs/apps
If the developer then says it's perfectly fine to drag the application icon located in the Applications or Applications > Utilities folder to the Trash, then you can do that. These types of programs are what we call "self contained" meaning everything it pretty much requires is inside the Application icon which is really a hidden folder called a "package".
Since "self contained" programs or apps can be run from just about anywhere they are placed, like in User Account folders so only that User can run them, however for global use amongst all User Accounts on the machine and in most cases of installers, they are stored in the Applications and/or Applications > Utilities folder.
Keep your Downloads folder clear
It is not advised to keep downloaded programs in the Downloads folder, rather to keep this clear at all times except during a known active download as to be wary of bad websites that will cause a "driveby download" hoping one will click or run to infect their machine. The Downloads folder is not a storage place, rather if you wish to keep a installer, place it someplace else in your User folders, like creating a folder called "Installers" or "Downloaded PDFs" and keeping them in your Utilities or Documents folders in your Home directory.
Concerning appdelete/appremoval type software
It is not advised to use "appdelete" type programs for the fact that there are hundreds of thousands of programs/apps and developers changing them all the time, thus it's almost impossible to keep up with all the changes. So as a result many of these appdelete type programs rely upon using a search feature and hoping the developer tagged their files with a name to locate files, which is not always the case. Accidents occur as users of these type programs delete other files or not get all parts installed by the developer.
Many developers use other developers software, like Pace for copy protection or Soundflower for a audio driver, when they install their software, thus the appdelete type software misses these files installed in the OS X kernel which then later get outdated or have security issues that are not fixed as the parent program is missing that does the updates.
The Dock
The Dock doesn't contain real programs, those are what's called "Aliases" or Windows users would know as "Shortcuts" which direct to the actual program, file or folders located elsewhere. To show the location of the real item in the Dock, right click and select Open > Show in Finder. The item there is the real thing, that's what is dragged to the Trash to delete (then Finder > Empty Trash to permanently delete it). 
To delete the icon off the Dock, merely drag it's icon off onto the Desktop area and release, it does a puffy smoke thing and disappears.
To place a mistakenly deleted Alias off the Dock back on, locate it by clicking on the Smiley  Face in the Dock to open a new Finder window, then navigate to it's actual location and drag it's original item into the Dock until it makes room and release. If you accidentally drop the icon on the Desktop, place it back in it's original location first, then attempt the Dock again.