Twitter finally lets you schedule tweets natively. It was only previously available via the ads manager or using a third party platform like hootsuite.
Do note that its not available on the twitter app yet. It's only available via twitter.com
Here's how to schedule tweets via twitter.com
Go to twitter.com and compose your tweet.
Once you have composed your tweet, click on the calendar icon on the bottom to bring up the scheduling window.
Click on the drop-down menus to set the desired date & time that you need your tweet to go out.
Once you have set the date & time for your tweet, click confirm.
Click on "schedule" to finish scheduling your tweet.
That's it, your tweet will be live according to the date & time that you've set.
Although tweet scheduling is not something new, scheduling from twitter.com is new. This is especially useful for tweets where you have to tag someone on a photo in the tweet or if you don't use a third-party platform to schedule your social media.