The main uses of the present perfect tense include describing recent actions, talking about life experiences, and expressing unfinished actions. The present perfect is used to describe a recent action or ask if something has happened recently. It is also used to talk about important things that have been done in one's life. Additionally, the present perfect is used to describe actions that started in the past but continue in the present. Unfinished time expressions like 'today, this week, this year, in my life' are typically used with the present perfect tense as well as adverbs like 'yet, already, just, ever, and never.'