You should always read the detergent manufacturer’s guidelines for the correct amount of detergent to use. Usually, the amount is based on the load size. Even if the manufacturer instructions say to put an amount that exceeds the Max Fill line, you should NOT exceed the line. You can switch to a more concentrated detergent or run a smaller load size, so you don't use too much.
Too much detergent can cause oversudsing which can lead to problems with your washer. It can also trap dirt and redeposit it on your clothes. On the contrary, putting too little detergent isn’t good either; your clothes may not get as clean.
You’ll want to try using the least amount of detergent possible to get your clothes clean. This will save money and prevent excess detergent from building up in your washer.