I would suggest using a table where you restrict formatting and editing to certain cells. (For more on setting up the table, see the article at http://word.mvps.org/faqs/tblsfldsfms/LinesInForms.htm.) Users can type only in the cells that you mark as editable and spellcheck will work.

To restrict the document: On the Tools menu, click Protect Document. In the Restrict Formatting and Editing pane, select "Allow only this type of editing in the document" and choose the "No changes (Read only)" option. Then select each location where you want to allow editing, and click the check box under "Exceptions (optional)." Finally, click the Yes, Start Enforcing Protection button, and specify an optional password.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional