Is there an app where you can add contacts or numbers to a list and anyone on that list will have their text messages auto deleted when they try to send you a text? Preferably one that can have this list be password protected.
When you block a number it automatically blocks all incoming calls and messeges from that number and also deletes all of the conversations you have had with them. This is so they won't be able to reach you at all and no matter what they do they won't be able to contact u. When you block a person it also earases their phone number. If you try to call or text them it also won't go through since you have already blocked them. There Will be no problem since neither of you can contact each other . It is the best way to go. Hope I could help.
Currently you don't need an external app for this, it has been a feature of Android since long time. Messages from blocked senders are deleted upon arrival so they don't even appear on your device.
Go to Phone -> More -> Settings -> Call blocking -> Block list and add the number you want to block.
Alternatively, go to your phone log or SMS list and select More -> Block number.
I've read all these answers but for anyone using a Samsung mobile phone unfortunately the phone keeps the messages from the number blocked and stores them funding blocked messages in settings. This is a seriously strange idea and not helpful if you are trying to not see messages that are upsetting or aggravating you. It also shows when a blocked number has called you
You can just download an app from Play store - it can block text msgs and even phone calls. Try Truecaller , add the contact to the Blacklist which will lead to the block
I recommend you to try SpamHound SMS Spam Filter (for iOS https://itunes.apple.com/app/id1263185195, for Android https://play.google.com/store/apps/details?id=com.redwerk.spamhound). In this app, you can create filtering rules that block certain senders or messages that contain special text. All spam messages will be sent to the Junk folder, and you will not receive them. Hope, with SpamHound you will get rid of annoying spammers!