The tense of any verb indicates to the reader when the action of the verb happens. Tenses are one of the main triggers for your audience. It can help an author build suspense, foreshadow, or reflect. It is one of those little things in written work that are often overlooked. There are three main tenses. The present is used to describe something that currently active or is constant. The future tense indicates something that will occur in the future or is imminent. You can also use the future tense if the odds are good that something will happen. The past tense is used to reflect on actions that have already taken place and ended. This is often used to describe situations and reflect on history.
Tenses of verbs are displayed at the ending of the words. For past tense -ed is often found on the end of words. For present tense -s is often found on the end. In most cases, you are going to want to keep your use of tenses consistent, but there are times when changing tense is required. This is often the result of a time shift from the past to present. Learning to master the words that result from a shift in tense, is the key to being highly proficient.