Regarding the spell check, Microsoft states:

“There is no spell check option in Outlook.com. To check your spelling, you’ll need to use your web browser. Spell checking is available in Microsoft Edge, Internet Explorer 10 and later versions, and current versions of Firefox, Chrome, and Safari. Check the options for your web browser to learn more about how to check spelling.”

Fortunately, most web browsers and operating systems now have built-in spell checkers. You’ve probably seen the spell checker in action if you post messages online or use an online email system; a red line will appear beneath words the spell checker doesn’t recognize. 

Most of these browser spell check features are enabled by default, so you don’t even need to hunt for how to turn them on. However, if spell check is not enabled, or you want to disable it, here are instructions for locating those settings in popular browsers and operating systems.

Spell Check In Chrome

For MacOS, in the top menu with Chrome open, click Edit > Spelling and Grammar > Check Spelling While Typing. It is enabled when a check mark appears beside the option in the menu.

For Windows:

In the top right corner of the browser window, click the three vertical dots to open the menu. Click Settings in the menu. Scroll down in the Settings window and click Advanced.   Scroll down to the Language section and click Spell check. Next to the language you want spell checking to occur, such as English, click the switch. It will move to the right and turn blue when enabled.

Spell Check In MacOS and Safari

Very similar to Chrome, in the top menu with Safari open, click Edit > Spelling and Grammar > Check Spelling While Typing. It is enabled when a check mark appears beside the option in the menu.

The Mac operating system, MacOS, also offers spell checking features. To adjust these, follow these steps:

Open the System Preferences app. Click Keyboard. Click the Text tab. Check the text editing options you want enabled: Correct spelling automatically, Capitalize words automatically, and Add period with double-space.

Spell Check In Windows and Microsoft Edge

On a Windows system, the Microsoft Edge browser doesn’t check spelling; the spell check setting is actually a Windows setting. To change this setting, follow these steps in Windows 10:

Open the Settings window by pressing the Windows key + I. Click Devices. Click Typing in the left menu. Toggle the switch under the two options available, depending on which you prefer: Autocorrect misspelled words, and Highlight misspelled words.

Other Spell Checking Options

Browsers offer specialized plugins that can extend features or add new ones to your browser experience. Spell checking and grammar checking plugins are available that can not only catch misspellings but also advise you on better grammar.

One of these is Grammarly. It checks your spelling and grammar as you type in a web browser and be installed as a plugin in most popular browsers, such as Chrome, Safari, and Microsoft Edge.