Different match type of PPC keywords
There are mainly 4 match types in PPC, which are Broad, Phrase, Exact & Negative. There is one more modification of broad match which is known as modified broad match.
Broad
PPC company is a broad keyword, if you keep the keyword like this then your ad can show for ppc or company of ppc company as well. So whenever there is any match like this, you ad may be triggered.
Phrase
"PPC company" is a phrase match, here your ad will triggered when the search query contains ppc company together, so your ad will be triggered if the search query is ppc company in india but your ad will not show for query for query like indian company doing ppc, though it has both the term ppc and company in the query but ad will not be triggered since they are not together like the keyword you have choosen.
Exact
[PPC company] is an exact match keyword and here, you ad will only be triggered when the search query is exact to your keyword, so if the search query is ppc company, then only your ad will be shown but if the query is best ppc company, then your as will not be triggered.
Negative
For keywords which you don't want your ad to be shown, you can exclude them and they will be considered as negative keywords. So if you don't want your ad to be shown for people who are looking for job, then you can simply exclude job and any people who are looking for job in ppc company or ppc company job, your ad will not be shown.
BMM
+ppc +company is a broad match modifier keyword and for this keyword, myour ad will be shown when the search query contains both ppc and company into it, not neccessary they have to be together but if they are present in the query, ad will be shown.
So if someone is looking for ppc by indian company, your ad will; be triggered.
Hope this information helps.