What are create_user_table, create_cache_table and create_jobs_table migrations?

Just open the relevant migration files and see what is being created. You can delete them or modify them as needed; you are free to rerun the all of the migrations as you develop your application so your database schema is up to date with whatever you need.

php artisan migrate:fresh

Are they needed for a basic laravel application; no. But, your "basic" might be different from someone else's. If you want to use Laravel's built-in authentication, then it might be easiest to keep the provided users migration, adding any other columns that your application needs. Same for jobs and cache (if using the database driver).