When you purchase an ActiveX control, you buy a design-time license for the control. This license is installed on your PC when you install the product and it allows you to use the control in the applications you are developing. The products typically have various design-time licenses for sale. These range from single developer licenses to multiple seat and network licenses.
Usually when you buy a design-time license you also get permission to distribute unlimited copies of the control with your application as compiled object code.
When you distribute your application that uses an ActiveX control, you need to ship also the control in binary format (usually a .dll or an .ocx). Do not distribute the setup file that comes with the design-time license.
If a control has a design-time license it will usually install a license key when its setup program is run. The license key is usually entered into the registry although it can also be installed in a special file.
Having a design-time license allows you to use the control for developing applications.
When you have built and compiled an executable application that uses the control, you need to distribute this control together with the application so a customer can use it. Most of controls also support run-time licensing for this purpose.
At compile time a license key is embedded into the executable file and this key is then inserted into the control when it is created. The control checks this key and if it is valid the control starts up. Because a key is embedded into the executable, no license key is required to be installed on the customer's machine and only the ActiveX control's binary needs to be distributed.