Someone help! I don’t know how to correctly use the 了 particle. Does anyone have any tips?
You add 了 if the action is completed. example: 我16岁了
There are a lot of uses for 了, but the two most common usages are for indicating completion (like Jordan said) and in combination with other words like 太 (“你太好了”), 死 (“我饿死了”), and 极 (“那好极了”).
Here’s a wiki guide to the 了 particle. I hope this helps!