Azure Cognitive Search: Create Index

In Azure Cognitive Search, a search index is your searchable content, available to the search engine for indexing, full-text search, and filtered queries. An index is defined by a schema and saved to the search service, with data import following as a second step. This content exists within your search service, apart from your primary data stores, which is necessary for the millisecond response times expected in modern applications. Except for specific indexing scenarios, the search service will never connect to or query your local data.

"searchable": Full-text searchable, subject to lexical analysis such as word-breaking during indexing. If you set a searchable field to a value like "sunny day", internally it's split into the individual tokens "sunny" and "day". For details, see How full text search works.
"filterable": Referenced in $filter queries. Filterable fields of type Edm.String or Collection(Edm.String) don't undergo word-breaking, so comparisons are for exact matches only. For example, if you set such a field f to "sunny day", $filter=f eq 'sunny' finds no matches, but $filter=f eq 'sunny day' will.
"sortable": By default the system sorts results by score, but you can configure sort based on fields in the documents. Fields of type Collection(Edm.String) can't be "sortable".
"facetable": Typically used in a presentation of search results that includes a hit count by category (for example, hotels in a specific city). This option can't be used with fields of type Edm.GeographyPoint. Fields of type Edm.String that are filterable, "sortable", or "facetable" can be at most 32 kilobytes in length. For details, see Create Index (REST API).
"key": Unique identifier for documents within the index. Exactly one field must be chosen as the key field and it must be of type Edm.String.
"retrievable": Determines whether the field can be returned in a search result. This is useful when you want to use a field (such as profit margin) as a filter, sorting, or scoring mechanism, but don't want the field to be visible to the end user. This attribute must be true for key fields.

[nikhithas]

Is PDF also searchable using Azure AI Search?

[stevemiller]

I dont understand the point of feilds. What connection do they have with my data?