This document contains some hints to get you started, but it is not a comprehensive guide. To actually write an add-on, you will need to familiarize yourself with Anki’s source code, and the source code of other add-ons that do similiar things to what you are trying to accomplish.
Because of our limited resources, no official support is available for add-on writing. If you have any questions, you will either need to find the answers yourself in the source code, or post your questions on the development forum.
You can also use the add-on forum to request someone write an add-on for you. You may need to offer some money before anyone becomes interested in helping you.