There are so many in so many different countries specialized in so many different things that it’s totally impossible to give any recommendation. They vary from freelancers to companies with hundreds of employees.
Google HOW TO SELECT A WEB DEVELOPMENT COMPANY to find a lot of hits about factors that you might find relevant for making *your* website.
I’m locking this thread to prevent spam from companies that without any proof say they are the best in, say, Mumbai of Kyiv. Maybe you don’t even want to outsource your site to India or Ukrain.