Signal is a simple app for your phone - and you should install it and use it?
Why? well, for one simple reason it allows both iPhones and Android to message each other using data and not SMS or MMS. It also allows calls via data.
But the real reason is privacy - what you send and receive or say using signal is private.
It is free and literally took a matter of seconds to install and start using. It ties in to your phone number and contacts and just works.
But wait a second! Encryption is difficult because of validating keys. People have "key signing parties" for things like PGP email. How can you tell the person you are talking to is the person you think they are?
Well, signal actually makes that easy too - you can easily, when you meet someone, point your phone at their screen and it reads a fingerprint of their key and checks it matches. If ever it changes later the phone will tell you that there is a problem.
They make privacy simple, and the Investigatory Powers Bill has nothing in it to allow snooping on your texts and calls in the network, when using Signal. It does not outlaw using Signal either (would be hard to without outlawing https for access to banks too). As worded now it could try to order this non UK company to put in a back door, and they are pretty guaranteed to tell them to sod off. The source code is available and inspectable so even if they were compelled to comply it would be obvious.
You can even secure the message archive in the phone independently to any encryption the phone offers.
So, download, install and use Signal - why not?
As used by members of the House of Lords to protect their privacy...