In general Microsoft Office products provides options for  automatic spell checkand you can find this feature in Word 2007, Word 2010, Word 2013 and Word 2016. This feature can be turned on or off using Microsoft Word options.

Click on the File menu –> Options (In Word 2007 it is under Office button –> Word Options)

Select Proofing options and navigate to When correcting spelling and grammar in Word section. This has a checkbox with label as  Check spelling as you type. By checking this field, you can turn on the automatic spell check as you type in Word 2010.

Updated with readers comment, this seems to have solved the problem for most of the users- Thank You Maria. Find below the screen shot for the same

Spelling and grammar check in Word 2016, Word 2013 and Word 2010

The Review menu in Word 2013 has the option to check for spelling and grammar errors. Let us say you want to run through a document for spelling and grammatical errors then you can navigate to Review menu and click the Spelling and Grammar option under Proofing section.

If there any errors in the document then you should see a sidebar showing the error staring from the current page.

This should provide you with an option to Ignore or Change the error as shown in the above screenshot along with the suggestion.  Once you choose either Ignore or Change, the next error will be display and this process would continue till there are no more errors left in the document.

In case you want to change the language used for Spell Check to English (United Kingdom) then you can use the language box available at the bottom of Spelling and Grammar sidebar.

If there no more errors left in the document then you should notice the following Spelling and grammar complete message.

How to hide spelling and grammar errors in Word 

Word users can hide spelling and grammar errors clicking File menu –> Options link. (In Word 2007 it is under Office button –> Word Options)

Navigate to  Proofing Options and scroll down Exception for section. Under this section there are check box available to  hide spelling errors and grammar errors.

Disable highlighting spelling and grammatical errors

If your word document does not highlight the spelling and grammatical errorsthen probably you can check the settings mentioned below.

Let us say you have the following sentence with spelling and grammar errors and currently these errors are not highlighted.

Select the sentence and click the Review menu and navigate to Language section.

Select Set Proofing Language drop down value from the Language menu option.

 

This would display the following Language window. Un tick the check box with label as Do not check spelling or grammar and click Ok button to confirm and save the changes.

 

This would start highlighting the spelling and grammar errors in the sentence.

 

If this did not solve the problem then probably you check by enabling auto spell check feature