This is a difficult question to answer without more information. English grammar can be very simple, as in basic sentence structure, or it can be very complicated, as in advanced punctuation and verb tenses. If you are asking about someone's specific use of English grammar, it is best to ask them directly. However, there are some general guidelines that can be followed.
For starters, English grammar is not always as simple as it seems. There are many rules that must be followed in order to speak and write correctly. While some people may be able to get by without knowing all the rules, others find it very difficult to do so. This is especially true for those who are not native speakers of English.
There are many resources available to help people learn English grammar. There are online courses, books, and even apps that can be used for this purpose. The best way to learn, however, is to practice as often as possible. This can be done by reading, writing, and speaking as much as possible. There are also many grammar exercises that can be found online or in books. These exercises can help people identify areas where they need improvement.
In general, the level of English grammar in use will vary from person to person. Some people are more proficient than others. However, with practice and effort, anyone can improve their English grammar skills.