It is such a nice cool little program, and would be perfect with a Spellchecker Both on WordPad and Notepad for Windows 10. In order to check the spelling of words in your WordPad or Notepad document, you must copy the entire document and paste it into a new Microsoft Word or similar word processing application's. If Microsoft can update Paint in Windows 10 to Paint 3D and even add Bing to ancient Notepad, there has to be SOME incentive out there to give WordPad some love. It just seems odd that no one from Microsoft has said, 'Oh yea, this is a great idea! Our developers are considering this.' The generic answer is 'Oh, you can buy MS Office, or subscribe to Office 365, or use an Office competitor'.
Apple's text creator an editing tools have Spellcheck. English and Persian text-to-speech services, spell-checking software, etc. Windows 10's own Feedback Hub has Spellcheck, all the browsers have spellcheck. At the left column, select translators you like by clicking the check boxes. The problem is that even the most-basic writing tools have spell check on them. That explanation would be fine twenty years ago. One explanation was that' WordPad is considered a text editor, not a full Word Processor and adding a Spellchecker would be considered an 'advanced' feature'. If you go on the Microsoft Feedback Forums, use the Windows 10 Feedback Hub, do online searching, you will find that one of the most requested Windows 10 features is adding a simple Spellcheck to WordPad.