My daughter (14) immediately said CoWriter Universal especially if spelling is an issue. It can be used on an iPad, iPhone or Chromebook. It's the gold standard. It allows for word prediction that adjusts to the topic you are writing about. (ie If your topic is India but can't come close to spelling Taj Mahal it will know to suggest it.) The user can utilize both text to voice and voice to text while writing so they can get the correct word or choose between words that appear similar.
Read and Write is a Chromebook extension. It's not as good as CoWriter but the basic version is free. If her school uses Chromebooks this may be the first one to try but you will need to spend money to get the better versions. She can use it to edit worksheets if they are in PDF form.
For handouts not in digital form she can snap a picture and complete the form on her device using SnapType Pro. She can write using her finger and bypassing a pencil if needed. She can also use a stylus or type in the app.
My daughter finds the built in keyboard easier to use than external keyboard but that's just her preference. She can change the format to adapt to her typing style using just 2 fingers.
Dyslexia Keyboard is a paid keyboard add on for the iPad that helps with spelling. It's designed for dyslexics so it recognizes a lot of common misspellings and allows the user to select the correct word.
Grammerly will correct for punctuation, correct form of the word, correct choice of sound alike words, etc.
DD has a ton of exprience and has been working with an amazing Assitive Technology specialist so let me know if you need more info. These are just a few ideas off the top of her head.
Definitely have her work on voice to text. It has gotten much better in recent years. DD says iOS voice to text works better than any voice to text app she has tried.
