Hi juliapainter09,
The first thing you can try is changing the position of your Silent switch. Move the switch located on the left of your iPhone so that the orange isn't showing.
If you still have trouble I recommend removing screen protectors or cases from your iPhone. Then check the speaker's opening to see if it is blocked or dirty, this includes the earpiece at the top of your device. If need be, clean the speaker or earpiece with a small and soft brush. ensure the brush is clean and dry
If the issue persists, you may have to check the sound settings on your device. Go to Settings > Sounds & Haptics and then drag the Riner and Alerts slider back and forth a few times. If you still cannot hear anything your iPhone may need servicing
For more information on this subject please go to:
If you hear no sound or distorted sound from your iPhone, iPad or iPod touch speaker – Apple Support
I hope this helped, feel free to reply if you need anything further.
Jett