Chrome: To enable spell-check, click the Chrome menu button in the top right on the browser toolbar. Select Settings, and at the bottom, click advanced settings. Scroll down to Languages and click the Language and spell check settings.
Safari: Open a new Safari window and select the Edit menu and scroll down to “Spelling and Grammar” You will then select Correct Spelling Automatically.
Firefox: Firefox automatically checks the spelling of words that you enter in text boxes containing more than one line. As soon as you finish typing a word, it is checked against the words in the installed dictionary. If the word is not found in the dictionary, it will be underlined in red. When spell-checking is enabled, you can easily correct misspelled words. To correct the misspelled word, Right-click on it and select one of the suggested words at the top of the menu.
Edge: The spell check is automatically set to on.