Before defining goals that are measurable, you and your partner should clearly agree on how the goals are to be measured, before and after. For example, if a goal is to reduce the number of chargebacks from a customer within 6 months, then it would be as simple as looking at the G/L accounts that you post the chargebacks to.
Some goals are tougher to measure, for example, if a goal is to increase productivity for the workforce, it may not be as simple as running some financial reports. For goals like these, it's recommended to define what does "increase productivity" mean? Is it to reduce the printed documents? Is it to reduce the time between customer service calls? Once that's defined, the next question would be how to quantify and measure the goal.
When defining a goal, it should be SMART, as shown in the following image:
Define different goals for your company and for the partner that is going to implement your Dynamics NAV. Each party will be responsible for different parts...