When you create a new topic, and you post a specific question, you are likely to receive several answers. It can be valuable to our community members to see which answer solved your problem.
As topic creator, you can set your topic as solved. Find the reply that answered your question. Click on the three dots next to the Reply button, you will see a crossed checkbox, click on this to mark your topic as resolved.
I will let my test account reply to this as example. So I can then mark that answer, and also set this topic as resolved.