If i going to buy some products like mobile market using Tor browser, how to do buy a product and what is the safe way of buying products? is this safe and original?
Tor Browser is just a normal web browser except that it works to keep you anonymous. You can do anything with it that you can do on any other browser.
With that said, there are a few things that must be said:
If the company doesn't allow anonymous transactions or doesn't allow people using Tor to use their website, then you can't use Tor Browser
As soon as you log in or give someone your address then you are not anonymous anymore and so Tor Browser isn't doing much for you
If your question is about how to buy something illegal on a darkweb market, then that is against the stackexchange rules and you won't find what you are looking for.