To visit someone at their company in Engpsh, you can say:

"I'm here to visit [Name] at [Company]."

You can also say:

"I have an appointment with [Name] at [Company]."

Or, if you are unsure of the person's location within the company, you can ask:

"Excuse me, can you tell me where I can find [Name] at [Company]?"

It's always a good idea to be popte and introduce yourself when visiting someone at their company. You can say:

"Hello, my name is [Your Name] and I'm here to visit [Name]. May I have a moment of their time?"

I hope this helps! Let me know if you have any other questions.