According to Google Ads definition, keywords are separated into 4 categories which are Broad Match, Broad Match Modifier, Exact Match, and Phrase Match.

• Broad match: A broad match has the greatest reach while having the least importance. Your keyword will be matched to search terms that are variations of it or are deemed relevant by Google Ads. This means that your entire keyword does not even need to be in the search query. As a result, the broad match might occasionally waste Google Ads funds; therefore, it should be used sparingly and in conjunction with negative keywords. Your keyword will be set to broad match unless you indicate otherwise.
• Broad match Modifier: A broad match modifier is similar to a broad match but more complex. This method involves inserting a plus sign (+) before each term in your keyword that you wish to appear in a search query. As a result, the ad will appear only if the search term +[keyword] is present.
• Exact Match: An exact match is the most specific type. When you select this option, your ad will appear only if the person is searching for your exact keyword or a close variation of it, such as misspellings, singular and plural forms, stemming, acronyms, and abbreviations. If the exact terms are used in the search query but in the wrong order, the ad will not be displayed (or if the search includes extra words).
• Phrase Match: A phrase match is less specific than an exact match, but it is more flexible. When you utilize this type of ad, people might search for a term that includes your keyword or a close variation of it. Additional query terms can appear before or after your keyword, but not in the middle.