Get list of all registered companies

I am trying to fetch list of all registered companies list in my form, can you please guide me how to get my api key as i have tried using by creating my application then there are few keys with it, non of them work for me. please help

This forum now has plenty of information covering this topic - try the magnifying glass icon at top right to search.

“None of them work for me” - there are lots of possibilities for what could be happening. Try searching, then if you post exactly what you’re trying someone may be able to advise.

See e.g. this thread for some things to check: