We're a software company, including like 35 employees, working in a very specific field. We have 3 stakeholders, and each of them have like 30 percent of the overall shares.
We just can't differentiate between inc., and co., and ltd. and stuff like that.
Reading the internet won't help that much. For example, in this link, it's obvious that incorporation is for large companies, and we're not large yet. But we do intend to become large.
This is important to us, because right now we're working on our branding.
Can you guide us on this process please?
You must go see a competent business lawyer in Iran. There aren't any highly experienced entrepreneurs from Iran on this site -- yet. :)
To help you a bit, and bring a bit more clarity to you:
You must go see a competent business lawyer in Iran.
Usually an accountant isn't that necessary for this, because good business lawyers will know have some knowledge about the general tax situation. But if you feel the uncertain about your lawyers knowledge of tax law, then be sure to also see a good chartered accountant specialized in tax law.
You need to speak to an accountant who can guide you with this. You don't normally choose inc / co / llc, as it depends on what type of corporate structure you setup. And what structure you need is beyond the scope of this answer. It will depend on your business goals, jurisdictions you operate in, shareholders etc.
In the UK when I start a limited company it has a "Ltd" ending... If it was a limited Liability partnership, it would have "LLP" ending. In Dubai it could be Limited Liability Corporation (LLC), India Could be a Private Limited Company (Pvt Ltd). So, you see, it depends on your business entity and where that is registered.