Navigating Employee Visa Processes for IT Assignments in the UK, US, and Japan: Need Guidance and Insights

We are an IT company and need to send our employees on assignment to the UK/US and Japan. Can anyone please help me understand how to obtain visas for our company to send IT professionals to the UK, US, and Japan? What is the process? Is there any concept of a block visa for companies.

Can there be help available from contractors or associates in the host country on visa? How much does it cost to get the visas done for employees, and how much time does it take? Can anyone help and guide?

Hi, I am currently working as a software engineer for the past 14 months in one of the MNCs. I got an offer to go to the US. However, as I am from a Mechanical Engineering discipline, I was rejected for the visa process. I heard that mechanical engineers should have at least 3 years of IT experience. Please help me out with this issue.