With a QWERTY keyboard I would suggest the International Keyboard.
You can type very efficiently all the accents (not only for the French language; I use it, for instance, to type German diacritics as well).
It suffices to learn some shortcuts and voilà.
Everything is thoroughly explained in the following link:

http://sites.psu.edu/symbolcodes/windows/codeint/

For Ubuntu users see

https://www.wikihow.com/Change-Keyboard-Layout-in-Ubuntu

For Mac users (thanks @Larme) see:

https://support.apple.com/kb/PH25643?locale=en_US

Regarding the second part of your question, may be I am a little bit purist, but I consider inacceptable writing French (even in textos) without diacritics.
In this way one will never master the French orthographe. French accents play a crucial role in the language and their absence may change completely the meaning of words (common examples: a/à, ou/où, du/dû and so on…).

Of course, this is my point of view. I am not a natif speaker but I know that many people (especially the younger ones) do avoid accents or use some astuces in order to decrease the time necessary for typing the message.

cc ca va? Jspr ke tu va bi1

http://www.ikonet.com/fr/blogue/technologies/langage-texto-francais/

Français 2.0…

It won’t be correct French, but it is of course accepted in informal emails since the writer has a foreign keyboard. You are not expected to copy and paste letters. Some people add a P.S. explaining why they couldn’t use accents when it’s not obvious for the recipients (sometimes seen on internet forums), but you don’t need to do it if the people you write to know you and know where you are.

If you had to write e.g. a Master thesis in French, now that would require you to use correct French, including accents. Then it would be best to invest in a French keyboard and save hours of tedious copy-paste.

It heavily depends on the person you’re writing to: I’m a Belgian (Flemish) and I’ve worked for several years in the French speaking part of the country, where I’ve done a large effort to speak/write the French language as correct as possible.
If anybody would have written me a French e-mail without any accent, I would have replied “Pardon?”, meaning “I don’t understand what you are writing.”, just to make the point.
Even using an AZERTY keyboard, I did have some issue writing French text (the characters ‘Ç’ and ‘œ’ are not present there too), but I’ve solved this by learning the ASCII codes by heart (199 and 156 in the mentioned cases), and in order to type those characters, I type ALT+0199 or ALT+0156. You might do this for the normal accent characters (just write them on a piece of paper, and put it in front of you, after a short while you’ll know them by heart).

For your information:

é  ALT+0233
è  ALT+0232
ê  ALT+0234
à  ALT+0224
â  ALT+0226
ù  ALT+0249
û  ALT+0251

(You might find all those back using the Windows program “Character Map”)

Good luck

I strongly recommend using the spell checker as much as possible (it’s not hard to add the languages you need and switch between them). It should be available either in your browser or in whatever mailing software you’re using.

That should work for most accented words.

Then I think it’s important to use accents with participe passé, to differentiate between “mange” and “mangé” for example.

But basically, if a native can deduct the accents the spell checker will, and if not there’s an ambiguity and you probably should copy and paste.

I recommend using a Compose key. It’s built-in in Mac OS and Linux(usually activated somewhere in Settings→Keyboard) and there’s a very good open-source Compose key for Windows called WinCompose.

How it works is that you press a key chosen by you as the Compose key(I like to use menu; between alt gr and ctrl) and then a sequence of characters to combine. Then Compose→e→’⇒é and such; a lot of different symbols can be produced this way.

To add to the personal experience, I’ve spent a lot of time on English keyboards not knowing the tricks to do accents under Linux and writing to French people or participating on French forums. All very informal contexts. I did get people complaining and pleading with me to get some accents already.

It can get wearing to read unaccented French, because a lot of common words are distinguished only by their accents – où/ou, à/a, conjugations of verbs of the first group… It makes it an extra effort to parse the text, like when someone makes lots of spelling mistakes. If the person is likely to make language mistakes on top of that it might get downright hard to understand.

I’d say that you “can” do it, in that you won’t be the first or last person to do it and plenty of people won’t care, but some will.

(to add to the ASCII codes info, if you don’t want to write them down or memorize them, know that they follow a specific pattern. Knowing it you can find the correct letter in a few tries, and over time you can end up learning the codes that way.)

As a native French speaker and French teacher to foreigners, I would definitely recommend that you use the accents.
If you don’t, it is no longer French, even in an informal email or a text.

When I was having exchanges in French in environments that did not provide support for accented letters, I was taught to write the accents after the letters. You can definitely get used to it.

So instead of “ma chère, un hôtel en été ça coûte !”, you’d write “ma che`re, un ho^tel en e’t’e c,a cou^te !”.

Of course using accented characters is preferred.