Hi,
I and my husband are US citizens, residing outside US for last couple of years. We want to buy a property in the US. We have our bank accounts as well as credit cards in the US, however our primary income is outside the US.
Can we get mortgage loan for buying the property?
If yes, what is the process?
Do we need some kind of pre approval?

I see no obstacle to getting a mortgage. Each lender has their own criteria, so you start by contacting banks and loan companies, either on the phone or online, and narrowing down some choices. Types of loans and fees will vary, so you have a lot to learn about terms, and what may seem like a good deal might not be. It's actually a complicated process that can have pitfalls and frustrations, so be prepared. The entire mortgage industry is still recovering from the disasters of the last 5 years, and all lenders are wary and demanding.

It is best to find a lender local to the property you want to buy. They will appraise the property (at a cost to you) to see if they will lend you the amount you want to borrow for it.