The home foundation company should offer a structural engineers report that certifies that the home is structurally sound with regards to the foundation after the repairs are complete. This will be important should you plan to sell the house as you will be required to disclose that foundation repair has happened.
The outside of the house may show signs of foundation shifting. The most common signs are cracks in the brick work, stucco or even the siding of the home. Often this is over the windows, doors or where the garage attaches to the house.