If you live in a partner city or town and you submit a report on SeeClickFix, the relevant department will likely "Acknowledge" the post. This means someone from the city has seen your report, and will either directly send a team to fix the issue you reported or begin the process needed to fix the issue. Once the city has fixed your issue, an government employee will likely go to the website and close the report with a message.
If you live in a city that actively uses SeeClickFix, it is probable that the city will acknowledge and close many of the issues that come through the system.
However, if the problem is fixed before the city had the chance to "Acknowledge" it, you can close the issue yourself. Go to the issue page, type a message, select "Close this Issue" button and, click on the blue "Comment" button.