Transfer Data between Excel and Word

Hi
I have an userform in Excel that have 4 textboxes to enter Company Name, subject, Date and letter ID.
How can I use a button to open a Word Document with textboxes data on top of the page, that the user can type the body of letter there? the user shouldn’t be able to change textboxes data location or text of them.
After save and close the document,How can I add the letter to a list box in that userform?
after all, How can I show first 20 charectors of the body of letter, when the user select the letter in the list box?

Thank you for your help