Q.Why do I have holes in front yard
My yard has become very uneven. You can’t actually see any holes just by looking at yard but from short distance you can see the unevenness.
Perhaps your lawn has had some rodents tunneling under the sod.
Your lawn may even need some maintenance to improve it's appearance and health.
Here are some links that may help you.
https://www.gardeningknowhow.com/lawn-care/lgen/top-dressing-lawns.htm
https://www.gardeningknowhow.com/lawn-care/lgen/aerating-your-lawn.htm
https://www.gardeningknowhow.com/lawn-care/lgen/fill-uneven-lawn-low-spots-how-to-level-a-lawn.htm