Work Visas & Permits

I am a Canadian software engineer with a job offer from a US company. My friend told me I should look at a TN visa instead of H-1B. What exactly is TN and is it better or worse than H-1B for someone in my situation?

I have been on H-1B for 2 years with my current employer. I have a better job offer from another company. Can I switch jobs? Will my visa status be affected? Do I need to start the H-1B process all over again?

My company wants to transfer me from our India office to our US office. HR mentioned L-1 visa but did not specify which type. I am a senior software architect who also manages a team of 12 people. Which L-1 category applies and what are the requirements?

My wife will come with me to the US on an H-4 dependent visa. I have heard there is some way for her to get a work permit but the rules keep changing. What is the current situation for H-4 EAD?

I have a job offer from a US tech company and they mentioned sponsoring an H-1B visa. I keep hearing about a lottery and I am confused. Can someone explain the full process — registration, selection, and what happens if I am not selected?