Here a few items to note related to search in Lightning Experience:
- Not all standard objects and standard fields are searchable in Salesforce, check out this article, and this article to make additional fields searchable.
- For custom objects, Allow Search option must be enabled.
- You can filter your search result to a specific object.
- Limit the number of results by entering more specific search terms. For example, enter the full name and company (Mike Jones Salesforce).
- As you type, you will see suggested records:
- Recently accessed items
- Results that match Name field values
- Searchable Fields by Object in Lightning Experience
- Make additional fields searchable
- Find Information with Search
- How Does Search Break Up Information?
- Objects displayed in search results inconsistent between Users