Can anyone helpout me.....?

Who is the best web developer company in USA…?? I need a amazing and attracting website for our business purpose…plz help me.

That’s not really an appropriate question to be asking here.

I suggest you do an internet search for “web developer in …” (whichever area of the US you are based) and take a look at the results which come up. Look at their own websites and those in their portfolios. Pick out three or four you particularly like the look of, then search online for “reviews of x” to see if other people have posted feedback - good or bad - about them. Contact the companies yourself and ask questions - see how responsive and helpful you find each one. You might also be able to contact one or two of their existing clients, to hear how they’ve found the experience of working with the company.

At the end of the day, the choice comes down to you - exactly what you want the company to do, what your budget is, what your timescale is, how easily you feel you can communicate, etc.