What does mchc value 31.3 mean? how to bring the values up?

The initials represent the Mean (average) Cellular Concentration of Hemoglobin. By itself I don't consider the cited value anything more than low normal. If pared with a low red blood cell count or low hemoglobin value, it may represent an anemia for which treatment would be based on other factors not available in the post.

All laboratory/imaging results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. Talk to the doctor who ordered the tests. Having said that, if your hemoglobin is normal, it is not a cause for concern. Wish you good health!