The users can definitely protect and unprotect their Tweets. They can protect their tweets by restricting their followers, which means that only approved twitter followers can see their tweets.

There are two types of tweets, these are the public and the protected tweets. Users should be mindful that when they signed up for Twitter, the tweets are public by default, which means that any person can see and interact with those tweets. They can protect their tweets by updating their account settings. Once they have protected their tweets, they’ll be receiving a request when new people or other users want to follow them, in which they have the capability to approve or deny the request. Accounts that are following the user’s tweets prior to protecting them will still be able to view and interact with the protected tweets unless the users block them. They can block other users in two ways.

They can block them from a tweet or block them from a profile. If it’s from a tweet, they just have to click the MORE icon (…) located at the bottom of the tweet and then click on BLOCK. When blocking from a profile, they just need to go to the profile page of the account they wish to block and click or tap the gear icon. Choose BLOCK from the menu and click to confirm.