First, remember that photographs of code ARE NOT A THING.
If you post a code snippet, ALWAYS USE CODE TAGS:
How to use code tags: Using code tags properly
You may edit your post above but it is not necessary: there is no post required for Null Reference, EVER.
The answer is ALWAYS the same. ALWAYS.
How to fix a NullReferenceException error
https://forum.unity.com/threads/how-to-fix-a-nullreferenceexception-error.1230297/
Three steps to success:
- Identify what is null
- Identify why it is null
- Fix that