Hi Ros, you can go to tplinkcloud.com, click on Not Register, you will see
[SIZE=2]Already have a non-activated account? Click here
[/SIZE]https://www.tplinkcloud.com/register.php
Already have a non-activated account? Click here

OK, thanks for this, but no luck. My fault for not giving more information. I have an HS100 smart plug but no Alexa or any other device like it. I have a registered account on the TP-Link site but I didn't respond timely to the Verification email, which I guess is necessary. The plug works great when I'm sitting here at home on my own wifi account, iPhone in hand. But I understood that the KASA iPhone app would allow me to contact the plug "from anywhere" to switch a plugged-in lamp on and off. Is this not correct? Do I need to finish the verification process? Thanks so much for any help.

Yes, finish the verification process is the first step.
Enable the remote control is the second step.
You can follow the first part of the instruction below to do that.
http://www.tp-link.com/us/faq-944.html

I don't have Alexa and don't want one. Will this plug work without a voice assistant? If not, I bought the wrong thing.

no no, it's not my meaning.
The instruction is for alexa, since you don't have amazon echo, the instruction is not for your case.
Just the first part is useful for your case. You just need to follow the first step in the instruction to enable remote control.

I must be dense. In this thread there have been two links mentioned. When I go to tplinkcloud.com I get a log-on which after I've logged on takes me to a camera page: "No camera exists in this account!" It seems to be a dead end.

The second link mentioned here is tp-link.com/us/faq-944.html. That takes me to the Alexa set-up instructions. I'm not seeing the answer.

What you need to do is to login to kasa with your cloud account.
Press on the plug's name, then go to device settings on the top right, enable remote control.

Need activation code