How can I fix a leak in blue plastic tubing that goes to ice maker? The leak is under the sink and tubing goes under the house to fridge on other side of room.

Cut and splice the tube unless you want to replace the entire thing. Lowes/Homedepot has splices.

Is the pipe itself cracked and leaking, or (most likely) it is leaking at the connection under the sink. I would need to know what type of fitting is connecting the blue tubeing. If you could take a clear picture of the leaking area, I will try my best to help you solve this problem.
Please let me know.

Thank you. Went to OSH and bought the splicer. My son is going to put it on for me.

I am sure it will work out for you. You have a good son that helps you fix things. That is great.