How much time does it take to enable Community Tab on Youtube after reaching 1K subscribers

Once the limit of 1K is achieved one is supposed to get the tab activated automatically. As per the help topics available about this in the internet it is mentioned that one has to wait at least about one week time before this tab emerges in one's YouTube channel. To see this tab one has to turn on the custom channel layout. It is found by many channel owners that many times the community tab is given after a long time and not in 1 week as was indicated by YouTube in its declaration about it. The reason of this delay is not known but ultimately people are getting it. So one thing is that you may have to wait for some time.

Another thing is that there is one Google support channel for it where people are discussing this problem and even indirectly requesting YouTube for enabling this community tab in their channel at an earliest. You can also join that forum and present your problem. The forum address is https://support.google.com/youtube/thread/677076?hl=en

Have you enabled custom channel layouts as this is also a prerequisite for the Community tab to be visible?

You can do so by login into your youtube.com account and then from the left menu, selecting Customization and then Layout. You can add to the various sections related to videos / popular uploads / playlists / Channels and at the same time you can highlight your videos or any other videos on YouTube for your subscribers to watch when they visit your channel homepage and finally when done click "publish".