This requires Posts widget Pro from Elementor Pro.
Advanced query filters give an admin several options to filter posts such as by meta queries, taxonomy queries, or specific post IDs.
Prerequisite
Before the Advanced Query Filter works, you need to set the query ID. To do so, click on the Posts Widget, go to “content” tab then look for “Query ID” under “Query” section. You can enter any value string on this field.
Meta Queries
Meta Query Relation (AND/OR) – this will determine the relation between multiple meta query.
Meta key – the key in post_meta table to look for.
Meta value – the value to match in the post_meta table.
Data type – the expected datatype of the value in post_meta table (CHAR for string, NUMERIC for number, DECIMAL for float, and DATE for date)
Compare – the comparison operator to use when matching the meta value (eg. LIKE, =, > etc.).
For more information about meta query, please follow this link
https://rudrastyh.com/wordpress/meta_query.html
Taxonomy Queries
Meta Query Relation (AND/OR) – this will determine the relation between multiple taxonomy query.
Taxonomy – name of the taxonomy ( eg. categories, tags, etc). The plugin supports custom taxonomies.
Field – the taxonomy field to look for.
Terms – the value to match in the taxonomy.
Compare – the comparison operator to use when matching the meta value (eg. LIKE, =, > etc.).
For more information about meta query, please follow this link
https://code.tutsplus.com/tutorials/wp_query-arguments-taxonomies–cms-23090#the-taxonomy-parameters
Other Settings
Posts Ids – Enter value on this field separated by comma if you want to filter posts by specific post ids.
Custom Empty Message – when enabled, the message will appear in the post widget when the the filter returns empty.