What is the best way to pitch Website developers or agencies?

hi, my name is Toshit Garg, and I am the founder of Convertixo and we want to pitch our tool, it can convert any Website into Android and iOS apps
within five minutes, we want to offer them that they can offer it as an add-on to their Website Development service, we are willing to provide the access to the the tool for free for first 2-3 times so they can see how it works and they can easily charge their clients $200 per app for this.

what do you think is the best approach to do pitch them? Any help will be appreciated Thank you.