Whom should I contact in a IT company

I have an innovative project developed. Now I have to contact companies. All my friends are refusing to take me inside to his working company. To contact a company for suggesting my project companies contact form will be of no use (I tried). Now, I got some ways to find email address of any person of any company but I am been in a confusion whom to contact. Should I contact branch CEO? but he/she will be busy and I may not get appointment. Should I contact HR Manager? Does HR can help me? Is that relates anyway to the job of HR? Else whom should I contact?

Contacting engineering and developers will be of no use. I have to meet a decision maker in the company. Which job role(s) takes ideas from external individual(s)?

I'd suggest contacting someone in sales. It is their job to look for new business opportunities and build relationships. If they see value in what you have to offer, they will take it up the chain.

I recently read The Sales Bible by Jeffrey Gitomer where it is suggested to always start selling from the top. If you want to contact a business to sell something it is advised to contact the company's CEO. If they find your idea interesting enough to spend 5 minutes listening to you, they will forward you to the right manager in their organization. It might require more then one phone call and probably first you need to contant their assistant to get the five minute chance to present your product.

Welcome to sales! The first approach is to hire someone who already knows how to sell to companies. Just like programming, it's not something you can learn in 2 minutes.

Second, I strongly recommend that you talk candidly to your friends again: the fact that none of them were willing to help promote your product internally is a major red flag. If your friends won't even bother, why would someone who doesn't know you care at all?

Third, if you want to do this yourself, figure out how companies work, who the user for your product would be. Sometimes, the user can purchase. Sometimes the user has to go through a different department to get tools. Either way, whoever has the pain is the most likely to be interested and have enough motivation to push the process of purchasing forward.