The question is confusing, what exactly do you mean by "directly from online"? Just click a button in a web browser and it will install the entire distro? If so, pretty sure the answer is no; if you imagine something else, please clarify.

Others are answering what you technically asked, but I think that's not what you're looking for. What you need is a 'live USB version', you run it from a usb stick and can try it without installing anything in your main drive.

Here is the link to the page with the links in mxlinux.com.

Now you have to make another decision, which desktop you want to use. Mx Linux's got three, xfce (known for being less demanding on resources), kde (bit windows-like, not that resource hungry either. It's worth a try), and Fluxbox (I don't know anything about this one). You might as well download and try the three of them. Just flashing them to the usb to try another.

Now the process. First you need one or more iso files (downloaded from trustable sources like the one from mxlinux.org itself, you also can check the checsum, but maybe too nerd just yet), a USB stick (probably 16gb or even 8 could be enough, but I'm not sure exactly. Pick a fast one if you can, it'll feel quite snappier. THE DATA IN THE DRIVE WILL BE LOST), and Rufus (this is a program to flash the iso into the usb stick).

Now read the pages I linked, and maybe follow the links there for explanations, I cannot tell you how to use rufus since it's been ages since I've touched it, but it's not so hard. May get a couple tries to flash the iso into a bootable usb (meaning the computer can boot or start running the os in that drive) but you've got this! Run rufus and flash one of the isos into the usb stick.

Now try to boot it. Look up how to get into your 'boot menu' (preferable if available, and it works. But it might not..) or 'bios setup' on the internet. It depends on the brand and model. You'll have to turn it off, and push some key just immediately after turning it on again, with your flashed usb stick plugged. If we're lucky you must see some text menu that lets you chose it to boot, and you'll be running Linux in a few seconds, hopefully.

Now when you're ready to install one of them into your computer's drive you have two options, dual booting keeping windows and putting also Linux for which you'll need a free partition or ssd for it, or if you are convinced of getting rid of windows for good just chose the easy formatting options while installing and that'll be it (THE DATA IN THE DRIVE WILL BE LOST).

If something doesn't go as planned or you have any doubts don't hesitate to make follow up questions, it's normal if you have to repeat some steps or search the internet to troubleshoot something, but Linux has become super easy to install and use (it really is much worse with windows or Mac..) so good luck and welcome to Linux!

What's your use case? If you want to replace Windows on your device then the answer is not really, however, if you just want a Linux shell then you can pretty much one click install a Linux distro inside of Windows with WSL2

You can download a Linux distribution from the Internet, but you must use a tool like Balena-Etcher or Ventoy to "mount" that distribution (typically in the form of a .iso file) to an external media, like a USB flash drive. Then, you'd boot your system into that USB to install the Linux distribution to your machine.

I don't think there is, the closest would be a net install release but MX doesn't appear to offer that.

I think - and believe me, it wouldn’t be the first time I encounter this - that OP assumes Linux is like an app in Windows or Mac. Ao, grossly oversimplifying, Windows, MacOS and Linux are today’s most popular operating systems. An Operating System or OS is software that sits all alone directly on top of the hardware; therefore, a computer has only 1 OS. These are not interchangeable either, ie you cannot run Linux as an app in Windows or vice versa. Now, what you can do is download an image of any OS online. An image is in the end just a storage device copied into a zip file with a bit of extra data, that you can “unpack” back onto a storage device that can be used to boot your computer, just like windows.

I think this really highlights a gap in Linux adoption. This makes me wonder how many people would install Linux if they could just click one button in their web browser to guide them through the process of replacing Windows.

macOS, but only on a Mac

if i remember correctly, if you use balena etcher, you can flash an usb stick without first downloading the ISO, using the url

Adding to the already excellent answers: there is such a thing as WebFAI: https://www.tuxedocomputers.com/en/TUXEDO-WebFAI.tuxedo . In short, it is a web-based tool to pick and install your distro of choice.

I do not think that it will be helpful for OP, as MX is apparently not being offered. You may need a Tuxedo laptop for it as well. Hopefully other readersl will have a TIL moment though.