Not much to add really, but I'd say to give full details of all the things that are online these days, such as utilities, bank accounts, etc., so that your nearest and dearest can quickly see what bank accounts/investments you have, who your utilities are provided by, references for council tax and water rates, etc. In the past, it may have been a ballache, but usually all this could be found by wading through the paperwork in the house, but now things are online, there's often nothing "physical" to tell those left behind about such practical matters.
I'd also say not only to declutter, but to downsize whilst you're still able, i.e. move to a smaller, more suitable home, or assisted living or over 55 flat, etc., which will make mobility easier (i.e. lifts or all on ground floor), walk in shower rather than a bath, also move closer to local amenities such as shops, chemist, GP surgery, etc. The more you can do yourself, the less you're reliant on friends/family to do the drudgery and what time they spend with you can be quality time. There's also the aspect of "use it or lose it" both physically and mentally, so by moving and downsizing, you should be able to keep independent longer and do more for yourself for longer.
As others have said, wills, POA, letter of wishes for funeral (or better still a pre-paid, pre-planned funeral).
Do as much as you can in terms of modern technology, i.e. smart phones, laptop, apps, "smart" meters, Ring door bell, etc., and a brilliant idea above to say use Alexa or similar to get accustomed to voice recognition and what it can do, i.e. play music, listen to radio, turn on "smart" devices, etc. Tech is only going one way and the older you are, before you try to embrace it, the harder it will be- if you try to embrace it whilst you've got your faculties, you'll be able to use it for longer and can use it for your benefit rather than because you have to!