Silence setting

First, check the Mute switch on the left side near the top of the phone. The switch should be towards the screen to unmute the phone.

Next, check the volume setting. While viewing the HOME screen use the two volume buttons on the left side below the Mute switch to adjust the volume.

Also, check the Do not Disturb function. When it is enabled a crescent moon will be displayed in the status bar. The setting is in the Settings app.

Is Do Not Disturb enabled? Do you have an Apple Watch? Have you checked to see if the Mute switch is engaged?