I have yet to set up an Apple email address, but intend to now. Obviously I will be able to access it from the Mac book. However, I will need to also access it (occasionally) from my Android phone. So the questions are: a) Is there a web based portal to allow access from a browser? and b) will I be able to access from Android (web based or App-based).
Forgive me for having an android phone and brazenly admitting it!
You can access an Apple email address through iCloud.com using Safari on a Mac. Sign in with your Apple ID. If you try to do the same on an iOS device, that same address will take you (unhelpfully) to a web page which offers to show you how to set up iCloud on that device and not to the login page. But you may be OK on an Android device - I'm a good boy and don't have one to test it on ;-)
When you set up a new account in Apple's Mail, it will contact the server (based on the email address - in this case iCloud.com) and get all the settings it needs i.e. it just works. Whether the email client on an Android device will do the same I can't say but you have nothing to lose by trying it.
I also have an Android phone and have looked in to the possibility of using my iCloud email address on it. Apparently it is possible and if you go to the Google Mail app and press settings you will be offered the choice of adding a new account. However that is where the simplicity ends. It seems that you cannot use your iCloud password and must create an App Specific Password. To do this you have to turn on two factor authentication. At that point I abandoned the task for the present time as I did not wish to add complication to my life. I may try it again in the near future and iff successful I shall let you know.
For occasional use, I would go with Mick's suggestion of using iCloud.com. This provides the web mail portal that you mentioned.
iCloud is intended to be browser-agnostic so I would be very surprised if it did not work with Chrome on an Android phone (I believe Chrome to be WebKit based just like Safari, give or take a recent Google fork of WebKit, so the 'engine' is common).
I'm surprised at Lionel's difficulties with the Android mail client (app) since, AIUI, Apple's mail is essentially a standard IMAP service. Others may know more?
I think that apple does not like you to sign in to icloud on any mobile phone other than an iPhone. I tried it on Chrome, Firefox and Microsoft Edge for Android and all returned the message that the browser was unsupported. Incidentally I have used all the above browsers on a computers, both Mac and PC to access iCloud with success. I can understand that phones are more liable to theft etc. and apple has no control over android security,