It can be difficult to remember which article to use - or if you should use one at all - when learning English. You may have many articles in your language, or none at all! Whichever category you fall into, here are some tips to help you remember if and when to use an article in English:
1. Use a/an for singular, countable nouns. For example, “I ate an apple.” Do not use a/an for noncount or plural nouns, such as water, wine, flowers, etc. Remember that a/an means one!
2. Use the for things that are specific, or if it is obvious what we are talking about. If you say, “the girl walked by me,” the person you are speaking to knows which girl you’re talking about. If you say, “I forgot the homework,” you forgot that specific homework assignment. If you say “I forgot the homework” to your teacher, they probably know the homework you’re talking about!
3. You don’t need the when you are talking about general places. For example, “I went to church on Saturday” not “I went to the church on Saturday.” The person may or may not know which church, and it doesn’t matter if they do. The same goes for school, college, university, work, etc.
There are a few exceptions to these rules which require some memorization, but this is a good place to start. When you listen to native English speakers regularly, you’ll especially notice when they don’t use the!
Here's my source and another blog to look at as a reference: