block text messages from various email address

Delete your APN settings.

Ignore that. Deleting your apn settings will stop all texts and data from working. The only way to stop texts from emails is to call and have them block your number. That will block all texts from email including any legitimate ones.

Gee, there should be a way for the user to do that on a ATT website.

If they are scam/phish attempts, which it sounds like they are, there is probably very little that you or AT&T can do, especially if they are originating from spoofed email addresses that are constantly changing. Don't respond at all and just delete.

Thanks for all your input.   I contacted AT&T and they blocked all text messages that are sent to my phone that originated from a email address. 

That will also block any legitimate text messages that originate from an email address as well.

OttoPylot: At the moment, I only receive text messages from email addresses that are unwanted.  No worries.

It's great that our team was able to assist you, @Curt_Penland! There are options to handling nuisance messages. Let's look into that for you! 

When dealing with spam, including those with an email address, we invite customers to follow these instructions to report unwanted calls and texts.

Learn what additional actions you can take to guard yourself against texting scams. You will find all that and more under the section Report SMiShing right away! Here’s how.

We hope this info helps! Thank you for your participation in our Community/Forums.

Lar, AT&T Community Specialist

I still have no way of blocking these text messages that are send from email addresses.

The ATT Community Specialists did nothing and claims they assisted.   NOT!