By Adding or Removing File type extensions from the list of file name extension in SharePoint search, Search index will include/exclude the properties from files that we have added or removed. To include a file type in search, we have to check that the file type will support for default or any third party filter-based in SharePoint search.
To add a file name extension to the Manager File Types page,
Navigate to Application Management in SharePoint Central Administration and click on Manage Service Applications link.
In the list of service applications, select Search Service Application.
On the Search Administration page, Click on File Types in Crawling section. We can see the Manage File Types page.
Click on New File Type and in the File Extension box We have to provide the file type to add and click on Ok.
We can the File type extension in the list of file types on Manage File types page.
To remove the file types select the file type in the list of file types and select delete to remove.