I am connecting to the town water supply and would like to know how you connect to the main water line within my house? I am being told that you have to bring the line underneath the footing but I'm wondering is that necessary? Thank you

It can come in under the foundation or through the wall.

I am connecting to the town water supply and would like to know how you connect to the main water line within my house?
A lot depends on the area you live in and where your frost line is. I live in a mild climate where the water service is a few feet underground and then jumps up and enters the unit above ground.
In colder climes the water service is brought in under the frost line.
It will also make a difference if you're on a slab or have a basement.
Give us some details about your house and where you live and we can better answer you. Regards, Tom