Keywords are very important to rank any site in search engine. there are many types of keywords to classify intent:
Users looking for and answer to search specific question and information
Searcher find a specific site and page, navigational keywords help to improve CTR
Users looking for some services or brands, you can use commercial keywords to increase sales.
Transactional keywords help to complete an action or purchase
When a user searches for more than 3 words, it is called long tail keywords.
Relevant and similar words from Focus keywords are called LSI keywords.