Where can I go to replace my IPhone 11 battery

If your battery health has dropped below 80% and needs to be replaced, start here:

iPhone Battery Repair & Replacement - Apple Support

Short answer: Yes. At the very least.

Longer answer: If it turns on, go to Settings>Battery>Battery Health. If it's less than 80%, you need a new battery. If it's not less than 80%, you have some other problem that needs attention. Or, a new phone.

My phone is about 4 years and will not charge. Do I need a new battery