Use 'add to' when suggesting that something will make a positive difference or is beneficial. Your unique perspective will add to the depth of our project.
Pro Tip 2/3
Quantitative Increase
Implies a measurable increase in quality, quantity, or strength. Hiring more staff will add to our productivity.
Pro Tip 3/3
Emphasis on Contribution
Highlights an individual's or item's contribution as significant. Your donation will add to the success of the fundraiser.