If your tab has been written in compliance with the latest version of Ultimate Guitar Tablature Guide (https://www.ultimate-guitar.com/contribution/help/rubric) then the tab is usually approved and accepted within 48 hours (in most cases much sooner).
If your tab doesn't meet some of the Guide's requirements, then Tab Administrators or Tab Moderators or other Tab Authors of high level leave a helpful comment telling you how you can improve your tab. You have 5 days in order to revise your contribution.
After you correct the tab, it gets accepted.
If you didn't amend the tab during the 5 days, your tab will be corrected by the admins/mods so that it meets the requirements of the Guide and gets accepted as well.
If there are no corrections after 5 days and it's impossible to correct the tab without the author, the tab gets rejected. However, you can always resubmit the tab after you make the necessary changes.
The following tabs are always rejected:
2. Corrections of your tab that's already approved (correct the faulty tab rather than submit a new one)
3. Lyrics without chords
Ultimate Guitar Tablature Guide ---> https://www.ultimate-guitar.com/contribution/help/rubric
Tabs Pending Approval FAQ ---> https://www.ultimate-guitar.com/contribution/help/approvalQueueFAQ