Light limits in URP

If you use the default Forward rendering pathThe technique that a render pipeline uses to render graphics. Choosing a different rendering path affects how lighting and shading are calculated. Some rendering paths are more suited to different platforms and hardware than others. More info
See in Glossary, the Universal Render PipelineA series of operations that take the contents of a Scene, and displays them on a screen. Unity lets you choose from pre-built render pipelines, or write your own. More info
See in Glossary (URP) has a maximum of 9 lights for each GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary:

• 1 Main Light, which is a per-pixel light by default. This is the main Directional Light in your sceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
  See in Glossary, or the brightest light.
• 8 Additional Lights, which are also per-pixel lights by default. You can set them as per-vertex lights instead.

For more information about per-pixel and per-vertex lights, refer to Per-pixel and per-vertex lights.

There are also the following limits per cameraA component which creates an image of a particular viewpoint in your scene. The output is either drawn to the screen or captured as a texture. More info
See in Glossary:

• Desktop and console platforms: 256 Additional Lights
• Mobile platforms: 32 Additional Lights.
• OpenGL ES 3.0 and earlier: 16 Additional Lights.

The Main Light is always visible per camera.

To add more lights per object or per camera, use the Forward+ or Deferred rendering paths instead. For more information, refer to Choose a rendering path in URP

Additional resources

• Lighting settings in the URP Asset Inspector window