For Sponsored Brands, you can choose words that must be present in the shopper search in order for your ad to run.
Broad match modifiers can be added by adding the plus symbol "+" in front of the keyword. For example, if you use the keyword "+men shoes" with a broad match, then the ad will only match to searches that contain the word "men". The ad may match to "men sneakers" or "running shoes for men" but not to any search term that does not contain the word "men," such as just “sneakers” or just “running shoes.”
You can use Broad match modifiers when adding or editing keywords in the campaign builder, Campaign Manager, bulksheets, or through the ad API.