Those are the so called 'keyword matching options'. Answer to your question is here:
Broad Match - This is the default option. If your ad group contained the keyword tennis shoes, your ad would be eligible to appear when a user's search query contained tennis and shoes, in any order, and possibly along with other terms. Your ads could also show for singular/plural forms, synonyms, and other relevant variations. For example, you ad might show on tennis shoe or tennis sneakers. Run a Search Query Performance Report to see what keyword variations trigger your ad.
Phrase Match - If you enter your keyword in quotation marks, as in "tennis shoes" your ad would be eligible to appear when a user searches on the phrase tennis shoes, in this order, and possibly with other terms before or after the phrase. For example, your ad could appear for the query red tennis shoes but not for shoes for tennis, tennis shoe, or tennis sneakers. Phrase match is more targeted than broad match, but more flexible than exact match.
Exact Match - If you surround your keywords in brackets - such as [tennis shoes] - your ad would be eligible to appear when a user searches for the specific phrase tennis shoes, in this order, and without any other terms in the query. For example, your ad wouldn't show for the query red tennis shoes or tennis shoe. Exact match is the most targeted option. Although you won't receive as many impressions with exact match, you'll likely enjoy the most targeted clicks - users searching for your exact keyword typically want precisely what your business has to offer.
Negative Keyword - If your keyword is tennis shoes and you add the negative keyword -red, your ad will not appear when a user searches on red tennis shoes. Negative keywords are especially useful if your account contains lots of broad-matched keywords. It's a good idea to add any irrelevant keyword variations you see in a Search Query Performance Report or the Keyword Tool as a negative keyword. Learn more.
