My niece is looking for a job that you sit most of the time.

Does she have any computer skills? Data entry jobs don't require much standing.

Computers! I see Roberta beat me to it and yes, it's true. There's not a lot of getting up except for grabbing things from a printer, going to and from meetings and comfort breaks, that kinda thing.

There are also phone jobs although there are fewer of those than there used to be. Not just telemarketer and the like but things like receptionist. For that, she might have to occasionally get up to fill a copy machine or greet a visitor. I had to do both, way back when, when I worked as a receptionist.

She should also consider her commute as it sounds like she'd need to work somewhere that she could drive to, as that would be sitting, as opposed to public transportation which can be hit or miss.

Many office jobs from accounting to administrative assistant to customer service.

I would suggest if she is good with people and has a good phone voice to try customer service phone work as this would not require much in the way of education.

try billing dept